Rebels fighting to topple Syrian president Bashar al-Assad declared Damascus International Airport a battle zone today, while Moscow and Washington both sounded downbeat about the prospects of a diplomatic push to end the conflict.
Fighting around the capital city has intensified over the past week, and Western officials have begun speaking about faster change on the ground in a 20-month-old conflict that has killed 40,000 people.
But Russia and the United States, the superpowers that have backed the opposing sides in the conflict, both played down the chance of a diplomatic breakthrough after talks aimed at resolving their differences.
"I don't think anyone believes that there was some great breakthrough," US secretary of state Hillary Clinton said of a meeting with Russia's foreign minister Sergei Lavrov and international mediator Lakhdar Brahimi in Dublin.
"No one should have any illusions about how hard this remains. But all of us, with any influence, need to be engaged with Brahimi for a concerted, sincere push."
Mr Lavrov said the sides had agreed to send officials to another meeting with Mr Brahimi, but also sounded a sceptical note.
"I would not make optimistic predictions ... It remains to be seen what will come out of this," he added, noting that Mr Brahimi knows the chance of success is "far from 100 per cent".
Rebels, meeting in Turkey in the presence of Western security officials, elected a 30-member unified military command, giving prominent posts to Islamists and excluding some senior officers who defected from Dr Assad's army.
Washington and its Nato allies want to see Dr Assad removed from power. Moscow has blocked action against him at the UN Security Council, and while outsiders repeatedly point to signs of Russia losing patience with him, its stance has not changed.
The past week has brought a war previously fought mainly in the provinces and other cities to the threshold of the capital.
Cutting access to the airport 20 km from the city centre would be a symbolic blow. The rebels acknowledge the airport itself is still in army hands, but say they are blockading it from most sides.
"The rebel brigades who have been putting the airport under siege decided yesterday that the airport is a military zone," said Nabil al-Amir, a spokesman for the rebels' Damascus Military Council.
"Civilians who approach it now do so at their own risk," he said. Fighters had "waited two weeks for the airport to be emptied of most civilians and airlines" before declaring it a target, he added.
He did not say what they would do if aircraft tried to land. Foreign airlines have suspended all flights to Damascus since fighting has approached the airport in the past week, although some Syrian Air flights have used the airport in recent days.
Syria says the army is driving rebels back from positions in the suburbs and outskirts of Damascus where they have tried to concentrate their offensive. Accounts from rebels and the government are impossible to verify on the ground.
Reuters