DAMASCUS - Arab leaders called for UN action on Saturday as at least 38 people were killed in Syria amid growing concern that envoy Kofi Annan’s peace plan is failing and the country is descending into all-out civil war.

Annan himself warned of sectarian warfare, singling out Syrian President Bashar al-Assad and his regime as key to resolving the conflict.

Washington and Moscow agreed on the need to work together on Syria, a US official said following a phone conversation between US Secretary of State Hillary Clinton and Russian Foreign Minister Sergei Lavrov.

“Her message to him was: ‘we’ve got to start working together to help the Syrians with Syria’s political transition strategy. And I want our people to work together on ideas in Moscow, Europe, in Washington, wherever we need to’,” the official said. At a ministerial meeting in the Qatari capital Doha, Annan said bluntly: “The spectre of an all-out war with a worrying sectarian dimension grows by the day. “The situation is complex and it takes everyone involved in the conflict to act responsibly if the violence is to stop. But the first responsibility lies in the Syrian government and President Assad,” he said.

Up to 300 unarmed UN military observers have deployed in Syria since a putative ceasefire brokered by Annan went into effect in April as part of a six-point peace plan, which also stipulated that the army must pull out of towns and cities.

“I told Assad he must act now to implement all points of the plan, and must make bold and visible steps immediately to radically change his military posture and honour commitments to withdraw heavy weapons and cease all violence,” Annan said.

He also said he told Assad to release detainees, open Syria to international humanitarian aid and allow freedom of expression as “this is essential to demonstrate his seriousness to the Syrian people and the international community.”

Earlier, the Arab League’s ministerial committee on Syria had called on Annan, the UN-Arab League envoy on the crisis who met Assad earlier this week, to set a time frame for his mission. “We request Mr Annan to set a time frame for his mission because it is unacceptable that massacres and bloodshed continue while the mission is ongoing indefinitely,” Qatari Prime Minister Sheikh Hamad bin Jassim Al-Thani said.

“We demand the UN Security Council refer the six-point (Annan plan) to Chapter VII so that the international community could assume responsibilities,” he added. Chapter VII outlines action the Security Council might take, including military force, in response to threats to international peace, breaches of the peace and acts of aggression.

Arab League chief Nabil al-Arabi also said he had asked the Security Council to take strong action to protect civilians in Syria but did not raise the question of intervention.

“I sent a letter to the UN Security Council asking it to undertake all necessary measures to protect the Syrian people,” Arabi told AFP shortly before the opening of the Doha meeting.

Afterwards, Arabi told reporters the ministers “did not request a military action.”

Iran, meanwhile, accused Doha, Riyadh and Ankara of serving US and Israeli interests in Syria.

Their goal was “to weaken or topple Bashar al-Assad’s government or make it surrender,” General Yahya Rahim Safavi, top military aide to supreme leader Ayatollah Ali Khamenei, told Iran’s Fars news agency.

“Qatar, Saudi Arabia and Turkey are acting in the interests of the US and the Zionists to weaken the resistance axis comprising Iran, Syria and (Lebanon’s Shiite movement) Hezbollah,” he said.

In Syria itself, troops conducted raids in search of anti-regime militants and clashed with rebels in several regions, with the Syrian Observatory for Human Rights reporting at least 38 people killed — 22 soldiers, 15 civilians and one deserter.

It said fierce fighting between government forces and rebels was under way in the town of Ariha in Idlib province, with reports of heavy regime losses.

Tensions spilled over into neighbouring Lebanon, as clashes between pro- and anti-Damascus gunmen killed 10 people and wounded more than 31 in the northern city of Tripoli.

The London-based Syrian Observatory says as many as 2,300 of the more than 13,400 people killed in Syria since the uprising against Assad’s regime began in March 2011 have died since the so-called ceasefire began on April 12.

Because of the worsening violence and Assad’s failure to meet commitments under an agreed peace plan, the United States has warned that it may not agree to renew the UN observer mission when its mandate expires on July 20.