Media caption Victoria Nuland, US state department, says they fear the regime may be planning an attack on al-Haffa 
 
 The US has expressed fears that the Syrian government "may be organising another massacre" in the town of Haffa in Latakia province, where UN military observers have been denied access. 
 
 UN Secretary General Ban Ki-moon said it was vital that the observers should be allowed into the town. 
 
 He and peace envoy Kofi Annan expressed grave concern about violence there. 
 
 A BBC correspondent travelling with UN observers witnessed sustained and heavy shelling in the old city of Homs. 
 
 The UN observers are in Syria to monitor the implementation of a putative ceasefire, brokered by Mr Annan, which has all but collapsed. 
 
 'Civilians trapped' 
 
 Annan's six-point plan 1. Syrian-led political process to address the aspirations and concerns of the Syrian people 2. End to violence by all sides; army troops to stop using heavy weapons and withdraw to barracks 3. Parties to allow humanitarian aid 4. Authorities to free political detainees 5. Authorities to ensure freedom of movement for journalists 6. Authorities to allow peaceful demonstrations 
 
 "The UN made a particular appeal to be able to get into Haffa because it had heard concerning reports about regime plans," US state department spokeswoman Victoria Nuland told a news briefing in Washington. 
 
 "At the same time, if you follow Syrian media, they were claiming that the opposition would cause a massacre." 
 
 Earlier this month, activists said Syrian government forces killed 108 people in the region of Houla, in Homs province, and 78 people in the village of Qubair, in Hama province. 
 
 But Ms Nuland downplayed the idea of foreign intervention in Syria, saying the emphasis would remain on using political and economic measures to pressure the government of President Bashar al-Assad. 
 
 The Syrian government blames the violence on foreign-backed armed terrorist gangs. 
 
 In a statement, Mr Annan, joint envoy for the UN and Arab League, said there were "indications that a large number of civilians are trapped" in Homs and Haffa. 
 
 Later Mr Ban spoke of the "great danger" to civilians under fire. 
 
 "The secretary general underlines the importance of unimpeded access by UNSMIS to Haffa, amid reports of a build-up of government forces around the town," he said in a statement. 
 
 Syrian government helicopter gunships strafed rebel positions in Haffa, UN observers and human rights activists said. 
 
 Media caption The BBC's Paul Danahar: "I was watching a mortar land pretty much every minute" 
 
 Heavy fighting was also reported in Rastan and Talbisa, north of Homs city, "with artillery and mortar shelling, as well as firing from helicopters, machine guns and smaller arms", said a statement from the UN Supervision Mission in Syria (Unsmis). 
 
 A car bomb exploded in the city of Deir al-Zour, killing 10 people, the London-based Syrian Observatory for Human Rights said, quoting sources on the ground. 
 
 Fighting was also reported in Idlib province. 
 
 It is impossible to confirm these reports independently, as Syria heavily restricts journalists' freedom of movement. 
 
 Russia, which supports the Syrian government, called for Iran to take a role in ending the 15-month old conflict. 
 
 Last week, US Secretary of State Hillary Clinton rejected the idea of involving Iran, which she accused of "helping to stage-manage the repression" in Syria. 
 
 Russian Foreign Minister Sergei Lavrov will travel to Tehran on Wednesday to discuss the initiative, the foreign ministry said. ||||| A U.N. report released Monday includes Syrian government forces and their allied "shabiha" militias for the first time on a list of 52 governments and armed groups that recruit, kill or sexually attack children in armed conflicts. 
 
 In Syria, it said, children as young as 9 years old have been victims of killing and maiming, arbitrary arrest, detention, torture, and sexual violence, and have been used as human shields. 
 
 "In almost all recorded cases, children were among the victims of military operations by government forces, including the Syrian armed forces, the intelligence forces and the shabiha militia, in their ongoing conflict with the opposition, including the Free Syrian Army," the report said. 
 
 Secretary-General Ban Ki-moon's annual report on children and armed conflict during 2011 names 32 "persistent perpetrators" that have been on the list for at least five years, including the security forces of seven countries. That's double the number in 2010, and Ban expressed grave concern at "the unacceptably high, and growing, number" of long-term abusers of children. 
 
 Radhika Coomaraswamy, the U.N. special representative for children and armed conflict, said that while new crises erupted in 2011 "with a heavy toll on children such as in Syria, and also in Libya, violations against girls and boys have come to an end in other parts of the world." 
 
 But the so-called "list of shame" with 52 names _ including four new parties in Syria, Yemen and Sudan _ is still too long, she said in a statement. 
 
 A resolution adopted by the U.N. Security Council in 2005 took the first major step to prevent the victimization of young people in war zones by addressing the exploitation of children as combatants and identifying governments and armed groups that recruit child soldiers. In 2009, the council voted to also name and shame countries and insurgent groups engaged in conflicts that lead to children being killed, maimed and raped. 
 
 The secretary-general said the United Nations has received reports of "grave violations" against children in Syria since March 2011, when protests against President Bashar Assad's government began. 
 
 The report quoted a former member of the Syrian armed forces saying that in December, during protests in Tall Kalakh, his commander gave an order to shoot during the break-up of the demonstrations and he saw three girls, who appeared to be between 10 and 13 years old, killed. A former member of the intelligence forces was quoted as saying he witnessed the killing of five children in a secondary school during demonstrations in Aleppo in the last quarter of 2011. 
 
 The report said the Syrian military and the shabiha used children as young as 8 on at least three occasions last year. 
 
 In an attack on the village of Ayn l'Arouz in Idlib province on March 9, 2012, it quoted a witness as saying several dozen boys and girls between the ages of 8 and 13 were forcibly taken from their homes and "used by soldiers and militia members as human shields, placing them in front of the windows of buses carrying military personnel into the raid on the village." 
 
 The United Nations also has collected dozens of accounts of eyewitnesses from children as young as 14 years old who were tortured in detention, as well as from former members of the Syrian military who were forced to witness or carry out acts of torture, the report said. 
 
 Most child victims of torture described being beaten, blindfolded, subjected to stress positions, whipped with heavy electrical cables, scarred by cigarette burns and in one case subjected to electrical shock to the genitals, the report said. One witness reported seeing a boy about 15 years old die as a result of repeated beatings. Another 15-year-old repeatedly beaten with heavy electrical cables during interrogation reported at least 20 other children his age or younger being held in detention, it said. 
 
 The report detailed many other serious human rights violations against children across the globe. 
 
 For example, in Somalia, the U.N. documented 7,799 child casualties of conflict last year, just in the three main hospitals in the capital Mogadishu. It also documented the recruitment of 948 youngsters by the Islamic militant group Al-Shabab and 242 cases of rape and sexual violence. 
 
 In Afghanistan, the report said 1,325 children were killed or injured in 2011, 30 percent by improvised explosive devices placed by armed groups. It said 316 cases of underage recruitment were reported, the majority by armed groups notably the Taliban as well as the Haqqani network and Hezb-e-Islami. 
 
 "In 2011, 11 children, including one 8-year-old girl, were killed while conducting suicide attacks" in Afghanistan, the report said. "Some children unknowingly carried explosive packages." 
 
 In Iraq, the report said 146 children were reportedly killed and 265 injured as a result of violence last year, mainly by armed groups including al-Qaida and the Islamic State of Iraq. The U.N. said 294 children were also indicted or convicted of terrorism-related charges. 
 
 Since the uprising in Libya began in February 2011, the report said the presence of children in armed forces and armed groups "was broadly reported" along with numerous grave violations. It said child casualties were not systematically document but it said 129 cases of killing and 247 cases of maiming of children were recorded. 
 
 In Ivory Coast, the U.N. registered 271 cases of sexual violence, including six against boys. 
 
 On a positive note, the report said parties to conflicts in Nepal and Sri Lanka were taken off the list after they successfully completed Security Council-mandated programs to end the recruitment and use of children. It said five parties in Afghanistan, the Central African Republic, Chad and South Sudan entered into similar agreements last year.
– The US and UN are warning that the Syrian government may be organizing another massacre, this time in the town of Haffa, where UN monitors have been impeded, reports the BBC. International envoy Kofi Annan says he is "gravely concerned" about the escalation of violence, and reports of mortar, tank, and helicopter attacks on Haffa and its surrounding villages. "A large number of civilians are trapped in these towns," he warned. The Syrian regime is using "new horrific tactics" on rebellious areas, a State Department spokeswoman says, warning: "People will be held accountable." A new UN reports has, for the first time, placed the Syrian government and its allied militias on a list of groups that kill and sexually attack children, AP reports. The report found that in Syria, children as young as nine have been the victims of killing, torture, sexual violence, and arbitrary detention, and have been used as human shields.