WASHINGTON President Barack Obama has signed a secret order authorizing U.S. support for rebels seeking to depose Syrian President Bashar al-Assad and his government, sources familiar with the matter said. 
 
 Obama's order, approved earlier this year and known as an intelligence "finding," broadly permits the CIA and other U.S. agencies to provide support that could help the rebels oust Assad. 
 
 This and other developments signal a shift toward growing, albeit still circumscribed, support for Assad's armed opponents - a shift that intensified following last month's failure of the U.N. Security Council to agree on tougher sanctions against the Damascus government. 
 
 The White House is for now apparently stopping short of giving the rebels lethal weapons, even as some U.S. allies do just that. 
 
 But U.S. and European officials have said that there have been noticeable improvements in the coherence and effectiveness of Syrian rebel groups in the past few weeks. That represents a significant change in assessments of the rebels by Western officials, who previously characterized Assad's opponents as a disorganized, almost chaotic, rabble. 
 
 Precisely when Obama signed the secret intelligence authorization, an action not previously reported, could not be determined. 
 
 The full extent of clandestine support that agencies like the CIA might be providing also is unclear. 
 
 White House spokesman Tommy Vietor declined comment. 
 
 'NERVE CENTER' 
 
 A U.S. government source acknowledged that under provisions of the presidential finding, the United States was collaborating with a secret command center operated by Turkey and its allies. 
 
 Last week, Reuters reported that, along with Saudi Arabia and Qatar, Turkey had established a secret base near the Syrian border to help direct vital military and communications support to Assad's opponents. 
 
 This "nerve center" is in Adana, a city in southern Turkey about 60 miles from the Syrian border, which is also home to Incirlik, a U.S. air base where U.S. military and intelligence agencies maintain a substantial presence. 
 
 Turkey's moderate Islamist government has been demanding Assad's departure with growing vehemence. Turkish authorities are said by current and former U.S. government officials to be increasingly involved in providing Syrian rebels with training and possibly equipment. 
 
 European government sources said wealthy families in Saudi Arabia and Qatar were providing significant financing to the rebels. Senior officials of the Saudi and Qatari governments have publicly called for Assad's departure. 
 
 On Tuesday, NBC News reported that the Free Syrian Army had obtained nearly two dozen surface-to-air missiles, weapons that could be used against Assad's helicopters and fixed-wing aircraft. Syrian government armed forces have employed such air power more extensively in recent days. 
 
 NBC said the shoulder-fired missiles, also known as MANPADs, had been delivered to the rebels via Turkey. 
 
 On Wednesday, however, Bassam al-Dada, a political adviser to the Free Syrian Army, denied the NBC report, telling the Arabic-language TV network Al-Arabiya that the group had "not obtained any such weapons at all." U.S. government sources said they could not confirm the MANPADs deliveries, but could not rule them out either. 
 
 Current and former U.S. and European officials previously said that weapons supplies, which were being organized and financed by Qatar and Saudi Arabia, were largely limited to guns and a limited number of anti-tank weapons, such as bazookas. 
 
 Indications are that U.S. agencies have not been involved in providing weapons to Assad's opponents. In order to do so, Obama would have to approve a supplement, known as a "memorandum of notification, to his initial broad intelligence finding. 
 
 Further such memoranda would have to be signed by Obama to authorize other specific clandestine operations to support Syrian rebels. 
 
 Reuters first reported last week that the White House had crafted a directive authorizing greater U.S. covert assistance to Syrian rebels. It was unclear at that time whether Obama had signed it. 
 
 OVERT SUPPORT 
 
 Separately from the president's secret order, the Obama administration has stated publicly that it is providing some backing for Assad's opponents. 
 
 The State Department said on Wednesday the U.S. government had set aside a total of $25 million for "non-lethal" assistance to the Syrian opposition. A U.S. official said that was mostly for communications equipment, including encrypted radios. 
 
 The State Department also says the United States has set aside $64 million in humanitarian assistance for the Syrian people, including contributions to the World Food Program, the International Committee of the Red Cross and other aid agencies. 
 
 Also on Wednesday, the U.S. Treasury confirmed it had granted authorization to the Syrian Support Group, Washington representative of one of the most active rebel factions, the Free Syrian Army, to conduct financial transactions on the rebel group's behalf. The authorization was first reported on Friday by Al-Monitor, a Middle East news and commentary website. 
 
 Last year, when rebels began organizing themselves to challenge the rule of Libyan leader Muammar Gaddafi, Obama also signed an initial "finding" broadly authorizing secret U.S. backing for them. But the president moved cautiously in authorizing specific measures to support them. 
 
 Some U.S. lawmakers, such as Republican Senators John McCain and Lindsey Graham, have criticized Obama for moving too slowly to assist the rebels and have suggested the U.S. government become directly involved in arming Assad's opponents. 
 
 Other lawmakers have suggested caution, saying too little is known about the many rebel groups. 
 
 Recent news reports from the region have suggested that the influence and numbers of Islamist militants, some of them connected to al Qaeda or its affiliates, have been growing among Assad's opponents. 
 
 U.S. and European officials say that, so far, intelligence agencies do not believe the militants' role in the anti-Assad opposition is dominant. 
 
 While U.S. and allied government experts believe that the Syrian rebels have been making some progress against Assad's forces lately, most believe the conflict is nowhere near resolution, and could go on for years. 
 
 (Additional reporting by Tabassum Zakaria and Arshad Mohammed; Editing by Warren Strobel and Peter Cooney) ||||| By Elise Labott 
 
 President Barack Obama has signed a covert directive authorizing U.S. support for Syrian rebels battling President Bashar al-Assad's forces, U.S. officials told CNN on Wednesday. 
 
 The secret order, referred to as an intelligence "finding," allows for clandestine support by the CIA and other agencies. 
 
 It was unclear when the president signed the authorization for Syria, but the sources said it was within the past several months. 
 
 The Obama administration has said it will step up its assistance to the opposition in the wake of last month's failure by the U.N. Security Council to agree on tougher sanctions against al-Assad's regime. 
 
 Exactly what type of support the finding authorizes is also unclear. The Obama administration has ruled out arming the rebels for now, providing only nonlethal assistance, such as communications equipment. 
 
 Last week, the U.S. Treasury Department approved a license allowing the Washington Syrian Support Group to provide direct financial assistance to the Free Syrian Army. The Washington-based representative of the Free Syrian Army is allowed to conduct financial transactions on the rebel group's behalf but is not allowed to send military equipment. 
 
 During the war in Libya, Obama signed a similar directive authorizing covert assistance for rebels in the battle against Libyan leader Moammar Gadhafi. 
 
 The Obama administration has resisted arming the opposition, in part, because U.S. officials don't know enough about the rebels. 
 
 U.S. officials have told CNN that Washington is cooperating with countries that are arming the rebels, including Saudi Arabia and Qatar, to help find groups worthy of aid. Diplomatic sources have also said the United States is providing intelligence on Syrian troop movements, which is then passed to rebel groups. 
 
 Foreign policy experts on Wednesday urged the Obama administration to increase its support of the armed opposition. 
 
 Testifying before the Senate Committee on Foreign Relations, Andrew Tabler of the Washington Institute for Near East Policy argued the United States should start arming the Syrian opposition, but only under the right conditions. 
 
 "At this point, given the direction of the conflict, I think that what we need to do is assess which groups could we and should we arm at what point, and make that decision," Tabler told the Senate panel. "I think that we're actually at that decision, given where the conflict is going." 
 
 James Dobbins of the Rand Corporation agreed. 
 
 "The time has come to consider and pick those groups that are most consistent with our interest and our vision for the future and begin to advantage them in terms of the internal politics, by providing assistance, including perhaps money as well as arms and advice," Dobbins said. 
 
 Martin Indyk, a former U.S. ambassador to Israel now with the Brookings Institution, recommended arming the opposition, but in a "wise way." 
 
 "We need to do it in a way that, first of all, we understand who we're supporting and what their intentions are," Indyk said. 
 
 The State Department said Wednesday the United States has set aside $25 million for "nonlethal" assistance to the Syrian opposition, with another $64 million in humanitarian assistance for the Syrian people. 
 
 The humanitarian aid, which includes funding for the World Food Programme, the International Committee of the Red Cross and other aid agencies, helps support the tens of thousands of refugees streaming across Syria's borders to neighboring Turkey and Jordan.
– Syrian rebels have become much more organized and effective in recent weeks, and it appears the CIA deserves some of the credit. President Obama has signed a secret order, approved earlier this year, allowing the CIA and other American agencies to support rebels seeking to oust Bashar al-Assad, sources tell Reuters. It's not clear how much clandestine support the agencies are offering, but they have apparently stopped short of providing the rebels with lethal weapons. Obama signed a similar order during the Libyan conflict allowing covert support for rebels battling Moammar Gadhafi's regime. The State Department has authorized $25 million for "nonlethal" support for the rebels and another $64 million in humanitarian aid. Foreign policy experts told a Senate panel yesterday that the time has come for the US to start arming the rebels, CNN reports. "At this point, given the direction of the conflict, I think that what we need to do is assess which groups could we and should we arm at what point, and make that decision," an expert from the Washington Institute for Near East Policy testified. "I think that we're actually at that decision, given where the conflict is going."