Tripoli, Libya (CNN) -- As fighting continued Friday in much of Libya, regional organizations underscored the need to plan carefully and move quickly to speed the transition from crisis to democracy. 
 
 In New York, U.N. Secretary-General Ban Ki-moon said he had talked with heads of the organizations, which included the League of Arab States, the Organization of Islamic Cooperation, the African Union and the European Union. 
 
 "All agreed that the crisis in Libya has entered a new and decisive phase," he said. "All agreed, as well, on the importance of a smooth transition." 
 
 That transition must be based on inclusiveness, reconciliation and national unity, he said. 
 
 "Fighting goes on in many parts of the country," Ban said. "There is an urgent need to put an end to the conflict and restore order and stability. All agreed that, if the Libyan authorities request, we should be prepared to help develop police capacity, bearing in mind that the country is awash with small arms." 
 
 The effect of the fighting has been profound, he said. "There are widespread shortages of fuel, food and medical supplies. Reports on the ground suggest that the water supply to the capital and surrounding region may be in danger, putting several million people or more at risk." 
 
 Friday's meeting participants agreed that the international community "must come together with an effective, well-coordinated program of action," Ban said. 
 
 Over the longer term, they emphasized early support for elections, transitional justice and policing, and help in social-economic recovery, rule of law and institution-building, Ban added. 
 
 He called Thursday's action by the Security Council in unfreezing $1.5 billion in Libyan assets "a welcome step" but said Friday's participants agreed that more must be done to ensure a stable transition of power. 
 
 Despite the continuing fighting, Moammar Gadhafi's grip on power has slipped, said Principal Deputy Press Secretary Josh Earnest, on Martha's Vineyard with the vacationing President Barack Obama. 
 
 "It is evident that there is momentum on the side of the rebels as they continue to make advances and as they continue in their efforts to set up a new government in Libya," he said. 
 
 Asked about the whereabouts of Libyan leader Gadhafi, he said, "Right now, as I've been saying the past few days, right now there is no evidence to indicate that Gadhafi has left Libya." 
 
 Earnest called on Gadhafi "to relinquish power once and for all," turn himself in and be held accountable. 
 
 The comments came as opposition and NATO forces took aim Friday at the Gadhafi regime in Tripoli and Sirte as rebels worked to consolidate their power across the country. 
 
 British warplanes pounded a "large headquarters bunker" overnight in Gadhafi's hometown of Sirte, the UK Defence Ministry said. Tornado aircraft fired a salvo of precision-guided missiles into the city, which is east of Tripoli on the central coast. 
 
 Outside one Tripoli hospital, the smell of disinfectant was overwhelmed by the smell of rotting human flesh. Inside, dozens of bodies lay abandoned in a room. In other rooms lay more. Some were wearing military boots, some dressed in fatigues, some in civilian clothes. One man was overwhelmed with joy to discover his son among the wounded inside the hospital. But his joy was tempered by the fact that the son's wound -- a bullet to the chest -- could still prove fatal. 
 
 In the heart of the capital, rebels began exploring the vast network of tunnels that run underneath Gadhafi's Bab al-Aziziya compound and much of the rest of the city. The thick-walled hallways -- wide enough for three people to walk abreast -- appeared to have been built to protect their occupants from bombing. But NATO's assault on the leader's compound was visible in one part of the tunnel, from which the sky was visible through a hole dug out by a bomb. Elsewhere in the bunker was a professionally equipped television studio. 
 
 Other previously hidden areas were opened to public view. In Tripoli, a former U.S. airbase converted by Gadhafi into a military airport showed graphically that the longtime leader's military had begun to decay long before rebels picked up their guns against him in February: Long lines of helicopters and dust-laden jets once worth millions of dollars apiece sat rusting on the tarmac. This is also where Gadhafi parked his private jets. A tree sprouted from part of one runway. 
 
 The opposition said its forces made gains late Thursday as it closed in on Sirte, and clashes flared Friday in that region, considered by fighters as a hot war zone. 
 
 On Thursday, Tornado aircraft destroyed one of Gadhafi's few remaining long-range surface-to-air missile systems, near Al Watiyah, close to the Tunisian border, the ministry said. 
 
 The ministry said Tornadoes and Typhoons destroyed a loyalist-held command-and-control site in the Tripoli area, also on Thursday. Britain is a participant in NATO's mission to enforce a U.N. Security Council resolution calling for the protection of Libyan people against Gadhafi regime forces. 
 
 As for the airport, rebels said they controlled the facility but were struggling to secure an area east of it controlled by Gadhafi loyalists. 
 
 The rebels said Gadhafi loyalists were indiscriminately shelling the airport from a civilian village east of the facility in an effort to repel the advance of rebel forces. Rebels said they were cautious in their response to the incoming fire because of concern over civilian casualties. 
 
 An aircraft burned as loyalists resumed shelling the airport with mortars and Grad rockets, a CNN team that witnessed the attack said. 
 
 A 17-year-old rebel said he hates war but feels forced to fight until the war ends. At that point, "I'm going to see my mother. I'm going to see my family," said Louis al-Zinatni. "I'm going to remove this gun from my hands. It's not for me." 
 
 The reports of continuing fighting came amid world concerns over revenge killings by rebels and loyalists. 
 
 Amnesty International has gathered accounts from survivors of abuse in Zawiya by pro-Gadhafi soldiers and rebel forces. 
 
 Amnesty said it also uncovered evidence that pro-Gadhafi forces killed detainees at two military camps in Tripoli on Tuesday and Wednesday. 
 
 Escaped detainees said loyalist forces had used grenades and gunfire on scores of prisoners at one camp, while guards at the other camp fatally shot five detainees. "Loyalist forces in Libya must immediately stop such killings of captives, and both sides must commit to ensuring no harm comes to prisoners in their custody," Amnesty International said. 
 
 The InternationalCriminal Court has issued an arrest warrant for Gadhafi alleging crimes against humanity. 
 
 On the political front, the opposition National Transitional Council was moving its political base to Tripoli from its stronghold in Benghazi in eastern Libya. 
 
 Libya's rebel leadership on Friday pleaded with the United States and other countries to unfreeze more money, saying the funds are vital to establish peace and stability in the nation. 
 
 "Our friends throughout the world are talking about the procedures needed to bring back peace and stability," Mahmoud Jibril, a senior National TransitionalCouncil leader, said at an international conference in Turkey. "But we cannot do that unless we can fulfill our duties." 
 
 Though the National Transitional Council has been recognized by 57 nations as the legitimate representative of the Libyan people, the Peace and Security Council of the African Union failed to follow suit at a meeting Friday. 
 
 Nevertheless, the council issued a communique that urged the "formation of an inclusive transitional government." 
 
 It called for the "establishment of a constitutional and legislative framework for the democratic transformation of Libya, as well as for support towards the organization of elections and the national reconciliation process." 
 
 In Washington, a U.S. deputy assistant secretary of state, Aaron Snipe, said he was pleased that 20 countries on the African continent have recognized the National Transitional Council. 
 
 "The international community has come out very much in one voice to support the aims and the purposes of the Libyan people," he said. 
 
 CNN's Nic Robertson, Dan Rivers, Sara Sidner, Arwa Damon, Raja Razek, Jomana Karadsheh, Hada Messia, Barbara Starr, Chelsea J. Carter and Pam Benson contributed to this report. ||||| Libya rebels push on, bodies pile up 
 
 (CBS/AP) 
 
 TRIPOLI, Libya - Dozens of decomposing bodies were piled up Friday in an abandoned hospital in Tripoli, a grim testament to the chaos roiling the capital as Libyan rebels clash with forces still loyal to Muammar Qaddafi. 
 
 The four-story hospital was in the Abu Salim neighborhood, which has seen some of the heaviest fighting this week, although the facility was empty and it could not be determined when the men had been killed. The floors were covered with shattered glass and bloodstains, and medical equipment was strewn about. 
 
 One hospital room had 21 bodies lying on gurneys, while 20 others were in the hospital's courtyard next to the parking lot  all of them darker skinned than most Libyans, covered with blankets. Qaddafi had recruited fighters from sub-Saharan Africa. 
 
 Battle rages on as rebels hunt Qaddafi 
 
 Tunnels of Qaddafi's "underground city" revealed 
 
 Complete coverage: Anger in the Arab World 
 
 With Qaddafi still on the run and vowing to fight to the death, the rebels have struggled to take complete control of the Libya capital after sweeping into the city on Sunday. The fight in Abu Salim has been particularly bloody. 
 
 Bursts of gunfire were heard coming from an area near the neighborhood before daybreak Friday. Smoke rose from the area but a rebel at the scene early Friday said the fighting in Abu Salim had ended by nightfall Thursday. 
 
 Rebels hammered at least 10 buildings at Qaddafi's compound where loyalists were taking shelter Thursday. As anti-aircraft guns battered the buildings, there were huge explosions, and the air was clogged with smoke. At least three of the buildings burned. 
 
 One rebel involved in the battle, Mohammed Karami, said Qaddafi loyalists had "heavy weaponry, maybe even a tank." 
 
 CBS News correspondent Barry Petersen, reporting from less than a mile away, said the area had been contested for several days. 
 
 "There's sniper fire around the area, it's hard to get in... We're told there are some bodies on the street," Petersen said. 
 
 About 10 to 15 percent of the city is still held by Qaddafi forces, reporter Tom Popyk in Tripoli told CBS News Radio. 
 
 "These are entrenched fighters, with snipers on the rooftops," in areas filled with industrial and government buildings, said Popyk. "So it's very, very hard to do anything except go in there and attack." 
 
 Men believed to be Qaddafi supporters or fighters were left moaning and calling for water at a clinic attached to a fire station in Abu-Salim. Curious men from the neighborhood climbed stairs to look at the men, but none offered help. 
 
 One of the wounded said he was from Niger and denied any links to Qaddafi. Asked why he was in Libya, he said, "I really don't know." He did not give his name. 
 
 Qaddafi had recruited fighters from sub-Saharan Africa, and many others are in Libya as migrant workers. In the turmoil since the rebellion broke out, migrant workers from southern Africa have been harassed. 
 
 Associated Press reporters flagged down a cab to take some of the wounded from the clinic to a hospital. The driver at first agreed, but men from the neighborhood intervened, saying the men would have to be interrogated before they could be moved. 
 
 The opposition's interim government, meanwhile, moved forward with efforts to establish political control despite the continuing violence. 
 
 The National Transitional Council announced it is moving from the country's second-largest city of Benghazi in the east to the Tripoli. 
 
 A minister in the rebel government said Qaddafi's capture is not a prerequisite for setting up a new administration in the capital. 
 
 "We can start rebuilding our country," Finance Minister Ali Tarhouni of the NTC told a news conference late Thursday. "He (Qaddafi) is the one who is basically in the sewer, moving from one sewer to another." 
 
 "I have a final message for everyone who is still carrying arms against the revolution," he said, "to let go of their arms and go back to their homes, and we promise not to take revenge against them." 
 
 Even with his regime in tatters, Qaddafi has tried to rally his followers to kill the rebels who waged war for six months to bring down Libya's ruler of 42 years. 
 
 "Don't leave Tripoli for the rats. Fight them, and kill them," Qaddafi said in a new audio message broadcast on Al-Ouroba TV, a Syria-based satellite station. 
 
 Outside Bab al-Aziziya, Qaddafi's main military compound that was captured on Tuesday, was another grim scene, one that suggested execution-style killings of civilians. 
 
 About two dozen bodies  some with their hands bound by plastic ties and with bullet wounds to the head  lay scattered on grassy lots in an area where Qaddafi sympathizers had camped out for months. 
 
 The identities of the dead were unclear, but they were in all likelihood activists who had set up an impromptu tent city in solidarity with Qaddafi in defiance of the NATO bombing campaign. 
 
 Five or six bodies were in a tent erected on a roundabout. One of the dead still had an IV in his arm, and another body was completely charred, his legs missing. The body of a doctor, in his green hospital gown, was found dumped in the canal. 
 
 It was unclear who was responsible for the killings. ||||| Media caption The BBC's John Simpson reports on the 'last crimes' of the Gaddafi regime 
 
 The United Nations has called on all sides in the Libyan conflict to take steps to ensure there are no acts of violence and revenge. 
 
 It comes as reports emerge of abuses and alleged summary killings by both rebels and troops loyal to Col Gaddafi. 
 
 The UN has also agreed to release $1.5bn (£1bn) in Libyan assets - which had been frozen under sanctions - to help with immediate humanitarian needs. 
 
 Fighting has continued in Tripoli, which is now largely in rebel control. 
 
 Thursday saw gunfights erupting in the city's Abu Salim district, one of the few remaining Gaddafi holdouts in the capital. 
 
 At the scene The rebels are building up their forces to attack Sirte. I spoke to one of their officers who said there would be another day at least of getting things into position. There are, they believe, about 1,500 Gaddafi loyalists on the road between Ras Lanouf and Bin Jawad, and they have to clear them out of the way before they can get to Sirte. Another officer told me he thought there was a deliberate delaying tactic, putting those Gaddafi forces on that road in order to better prepare the defences of Sirte. Certainly we saw a lot of tanks being moved up yesterday [Thursday] and digging in for this smaller battle before they get to Sirte itself - they think that will take three or four days. Col Gaddafi was born in the desert, in a tent near what was then the tiny fishing village of Sirte. When he came to power, 42 years ago, he started building it up, almost as a rival capital to Tripoli. The African Union was founded there, which Col Gaddafi has always thought of as his foremost achievement. He poured money into Sirte, with the result that it remains very loyal to him. Watch Paul Wood's report on the road to Sirte 
 
 The rebels have also been attempting to reach Col Gaddafi's hometown of Sirte but have been met with fierce resistance. There were reports that Nato planes carried out air strikes on the city overnight. 
 
 Late on Thursday, the National Transitional Council (NTC) said it had now moved its political base from the rebel stronghold Benghazi to the capital. 
 
 According to a rebel spokesman, half the NTC leadership is now in Tripoli. But the BBC's Jon Leyne, in Benghazi, says NTC chairman Mustafa Abdul-Jalil and other senior officials are waiting for the situation in Tripoli to stabilise before they move. 
 
 The urgent process of restoring essential services and supplies, Libya's future effectively, is largely on hold until Col Gaddafi is killed or captured, our correspondent says. 
 
 Tortured and killed 
 
 UN human rights spokesman Rupert Colville said it was difficult to confirm reports of summary killings and torture, but said such incidents would be investigated by the existing Commission of Inquiry on Libya. 
 
 "We urge all those in positions of authority in Libya, including field commanders, to take active steps to ensure that no crimes, or acts of revenge, are committed," he told Reuters. 
 
 The UN has previously said some military action in Libya could amount to war crimes or crimes against humanity. 
 
 Earlier this week, the NTC's chairman, Mustafa Abdul Jalil, urged rebels not to engage in revenge attacks against pro-Gaddafi fighters, threatening to resign if his warning was not heeded. 
 
 The BBC's Rupert Wingfield-Hayes visited a hospital in the Mitiga district of Tripoli which had received the bodies of 17 rebel fighters. 
 
 Doctors said the group had been prisoners of Gaddafi troops in Tripoli and were tortured and killed as the rebels seized the capital earlier this week. 
 
 Dr Hoez Zaitan, a British medic working at the hospital, said about half the bodies had bullet wounds to the back of the head while others had disfiguring injuries to their limbs and hands. 
 
 He said the bodies had been examined for possible evidence to be used at a war crimes tribunal. 
 
 Meanwhile, the bodies of at least a dozen pro-Gaddafi fighters - two of whom had their hands tied behind their backs - were found on a roundabout in the centre of Tripoli. 
 
 There were reports that one body had an intravenous drip in the arm, and that others were badly burned. 
 
 Amnesty International says it has "powerful testimonies" of abuses by both sides in the coastal town of Zawiya, including allegations of violence by rebels against African migrant workers accused of being mercenaries. 
 
 On Thursday evening, the UN reached an agreement to release $1.5bn in Libyan assets after the motion was modified to remove a reference to the NTC. 
 
 South Africa had stalled the move, raising among its concerns that giving money to the NTC indicated officially acknowledging it as Libya's leaders - something it and the African Union have yet to do.
– The UN has unfrozen $1.5 billion in frozen Libyan assets to be used as humanitarian aid as it called on both sides of the conflict to avoid revenge killings, the BBC reports. The money had been seized by the US in the spring. It won’t go straight to the rebels, notes the New York Times: Instead, the US and international agencies will direct it toward humanitarian efforts. The head of the Transitional National Council pledged to “favor the countries which helped us” in accordance with “the support which they gave us.” With about half the Council in Tripoli, the city is largely in rebel hands—but fighting has continued, including reports of summary killings by both rebels and loyalists. Meanwhile, rebels have met opposition in their struggle to reach Moammar Gadhafi’s hometown, Sirte, which British planes bombed last night, hammering what Britain called a “large headquarters bunker,” CNN reports. Meanwhile, an empty hospital in the Abu Salim area—which has seen vicious fighting—held dozens of decomposing bodies, notes CBS News.