Syria has begun supplying details of its chemical arsenal, the world's chemical weapons watchdog said on Friday, as rebels agreed a truce with jihadists in a key border town.
A senior official also said Damascus wanted a ceasefire in the 30-month war, which has reportedly killed more than 110,000 people and forced more than two million to flee.
Iranian President Hassan Rowhani has offered to broker talks between the Syrian opposition and the Islamic republic's key ally in Damascus.
Hours before a deadline for President Bashar al-Assad's regime to provide details on its arsenal, the Hague-based group tasked with dismantling it said it had received an initial report.
"The Organisation for the Prohibition of Chemical Weapons has received an initial disclosure from the Syrian government of its chemical weapons programme," an OPCW statement said.
Its Technical Secretariat is now examining the details, it said.
The organisation has postponed a meeting of its Executive Council set for Sunday that had been due to discuss how to dismantle Syria's chemical weapons programme.
Damascus had until Saturday to supply details of its arsenal, in line with a US-Russian plan that helped prevent military action on regime targets following a chemical attack last month that killed hundreds of people.
The plan stipulates that Assad's regime hand over its chemical weapons and facilities, which would be destroyed by mid-2014.
But on Wednesday, Assad said in an interview that the task could take at least a year and cost a billion dollars.
On the ground, jihadist rebels fought fiercely for the town of Azaz on the Turkish border before seizing it Wednesday from mainstream Free Syrian Army (FSA) rebels.
The move by Al-Qaeda front group the Islamic State of Iraq and the Levant (ISIS) triggered the ire of the political opposition group the National Coalition.
It issued a rare condemnation of ISIS, accusing the jihadists of violating the principles of the revolution.
The Syrian Observatory for Human Rights said that the Northern Storm brigade, which is loyal to the FSA and was based in Azaz, has agreed to a truce with ISIS.
The deal was brokered by Liwa al-Tawhid, a powerful rebel brigade loyal to the FSA, which sent fighters to deploy between the two sides in Azaz, the Observatory said.
Symbolic and strategic
Azaz has both symbolic and strategic value as it was one of the first towns to be captured from government troops, in July 2012, by the FSA which set up its own administration.
Tensions have spiralled between some mainstream rebel groups and ISIS in recent months, especially in northern Syria, where the opposition controls vast swathes of territory.
Deputy Prime Minister Qadri Jamil, meanwhile, said the war is now in stalemate and Damascus would call for a ceasefire if long-delayed peace talks in Geneva take place.
"Neither the armed opposition nor the regime is capable of defeating the other side," Jamil told Britain's Guardian newspaper.
Asked what his government would propose at the stalled Geneva II summit, he replied: "An end to external intervention, a ceasefire and the launching of a peaceful political process."
The National Coalition's condemnation of ISIS highlighted the tensions within rebel ranks.
It accused ISIS of seeking to create a "new state inside the Syrian state", and charged that the jihadists have "links to foreign agendas" and had violated the spirit of the Syrian revolution.
The deployment of jihadists on the battlefield has deterred Western governments from providing the rebels with more than non-lethal assistance for fear that any weapons supplied might fall into the hands of extremists.
President Francois Hollande said on Thursday that France was in favour of sending the FSA weapons, but only "in a controlled environment" and "with a number of countries".
Washington has also repeatedly expressed concern about the risks of weaponry reaching groups loyal to Al-Qaeda.
On the diplomatic front, UN envoys were set to resume talks on a draft Security Council resolution that would enshrine a joint US-Russian plan to secure and neutralise Assad's chemical weapons.
US Secretary of State John Kerry said on Thursday that a UN report has proved the Syrian regime was behind a deadly chemical weapons attack in August that killed hundreds of civilians.
On Thursday, Iran's president said Tehran was ready to help facilitate dialogue between the Syrian government and its opponents.
"We must join hands to constructively work toward national dialogue, whether in Syria or Bahrain. We must create an atmosphere where peoples of the region can decide their own fates," Rowhani wrote in The Washington Post.