The main Syrian opposition grouping agreed to attend United Nations-sponsored peace talks which began in Geneva on Friday, reversing a boycott that had threatened to wreck the first attempt to find a diplomatic solution to the war in two years.
On the ground, opponents of President Bashar al-Assad said they were facing a Russian-backed military onslaught, with hundreds of civilians reported to be fleeing as the Syrian army and allied militia tried to capture a suburb of Damascus and finish off rebels defending it.
U.N. envoy Staffan de Mistura has invited the Syrian government and an opposition umbrella group to Geneva for "proximity talks", in which they would meet in separate rooms.
Until the last minute, the opposition High Negotiations Committee (HNC) had refused to attend. The group, which includes both armed and political opponents of Assad, had insisted it wanted an end to air strikes and sieges of towns before talks could start.
Late on Friday, a spokeswoman said the HNC were coming to Geneva for discussions with de Mistura and the United Nations. They did not intend to engage directly in a political process with the Syrian government.
The spokeswoman, Farrah el Atassi, said the HNC had received guarantees that their demands would be met.
De Mistura opened the talks on Friday by meeting the Syrian government delegation. He said that while he had not yet received formal notice that the HNC would attend, he expected to meet its delegation on Sunday.
U.S. Secretary of State John Kerry had made a major push to get the HNC delegation to Geneva.
"Secretary Kerry has been in touch with all of his counterparts, including this morning with (Russian Foreign Minister) Sergei Lavrov … and with others, trying to find a way, a formula, in which we can urge the delegation or some version of the delegation to show up here," a senior U.S. official said.
The Syrian government delegation, headed by United Nations ambassador Bashar al Jaafari, arrived at the talks on Friday afternoon but made no statement.
Another major force, the Kurds who control much of northeast Syria and have proven one of the few groups capable of winning territory from Islamic State, were excluded from the talks after Turkey demanded they be kept away. The Kurds say their absence means the talks are doomed to fail.
International diplomacy has so far seen only failures in a 5-year-old multi-sided ethno-sectarian civil war that has killed more than 250,000 people and driven more than 10 million from their homes while drawing in regional states and global powers.
De Mistura\’s two predecessors both quit in apparent frustration after staging failed peace conferences.
Since the last talks collapsed in 2014, Islamic State fighters surged across Syria and Iraq declaring a "caliphate", the United States and its European and Arab allies launched air strikes against them, and Russia joined in last year with a separate air campaign to support Assad.
Moscow\’s intervention in particular has altered the balance of power on the ground, giving strong momentum to government forces and reversing months of rebel gains.
The Syrian military and allied militia are seeking to build on gains in western Syria, and have turned their focus to opposition-held suburbs southwest of Damascus.
The aim is to crush rebels in the district of Daraya to secure the nearby military airport at Mezzeh, said Rami Abdulrahman, director of the Syrian Observatory for Human Rights, which monitors the conflict with sources on the ground.
Rebels had rejected a government deadline for them to withdraw from the suburb of Mouadamiya – home to 45,000 people – by Friday, said Abu Ghiath al-Shami, spokesman for rebel group Alwiyat Seif al-Sham.
More than 500 families had fled, he said. "They are suffering a shortage of food, medicine, milk – there is no power, nothing," he said, adding that 16 barrel bombs had been dropped on Friday.
A Syrian military source denied the use of barrel bombs, which have been widely documented in the war, and accused the opposition of exaggerating the conditions. "There has been progress by the army in the last days, some successes particularly in the Daraya area," the source said.
Rebels say the fighting is of more concern to them than the fate of the negotiations. Asked about the future of the talks, Shami told Reuters he was "a bit busy" dealing with the fighting.