Syria's warring sides headed Friday into a decisive day for the faltering peace process, under pressure to agree on an agenda to save the deadlocked Geneva talks from collapse.
Coming on what was expected to be the last day of the current round of talks, the second in three weeks, Friday's meetings are "a big test for whether this process will move forward or not," said a Western diplomat.
"We are in a dead-end, and I don't know if we will get out or not," the diplomat added, warning the prospects looked "grim".
The rival sides were meeting separately with UN mediator Lakhdar Brahimi Friday morning in a bid to break a deadlock which has seen them fail to even come together on an agenda.
"If (they) can't get an agreement on an agenda, I don't know how Brahimi will uphold a round three," said the diplomat, who asked not to be identified.
While the initial talks last month were viewed as a relative success for merely bringing the parties face-to-face, the current round has achieved little more since Monday than an endless restating of positions and trading of blame.
Washington, which backs the opposition, and Moscow, which supports Damascus, sent top envoys to Geneva this week to use their clout with their allies to help revive the process.
But after a meeting with high-ranking US and Russian diplomats Thursday, Brahimi admitted that "failure is still staring us in the face".
'A very bad omen'
The so-called Geneva II negotiations, which began on January 22, have so far done nothing to end the nearly three-year civil war that has claimed more than 136,000 lives and forced millions from their homes.
"We expected that the talks would be difficult. We didn't expect that (the parties) would be unable to compromise on an agenda, and that frankly is not good. That's a very bad omen for the process," said the Western diplomat.
The opposition National Coalition maintains that the only way forward is to create a transitional government that can guide Syria towards peace, without President Bashar al-Assad.
The regime says Assad's future is not up for discussion, and insists the priority must be halting "terrorism", which it blames squarely on its opponents and their foreign backers.
Brahimi has attempted to find a middle ground, suggesting the parties discuss the two issues in parallel.
The opposition has reluctantly agreed to the parallel track, but insists the talks on violence must focus on the regime's actions, including raining explosives-packed "barrel bombs" from helicopters.
Brahimi has said he has "tonnes of patience" and that he would "certainly not leave one stone unturned if there is a possibility to move forward".
But the Western diplomat cautioned: "I would not assume he will stay indefinitely," pointing out that the veteran Algerian peacemaker might have "concerns about his own credibility" if he allows the process to continue turning like a broken record with no progress in sight.
Russia's Deputy Foreign Minister Gennady Gatilov met the regime delegation chief, Syrian Foreign Minister Walid Muallem, on Wednesday and again on Thursday.
And the opposition delegation met with members of the Russian team and with US Under Secretary of State Wendy Sherman on Thursday.
It was unclear though if Washington and Moscow could push the sides closer to actual dialogue.
Opposition delegation member Badr Jamous was not optimistic, telling AFP: "Things are not positive ... I don't think there will be a third round."
- Homs evacuation 'painstakingly slow' -
Meanwhile, regime air attacks and fighting have sent the death toll in Syria soaring, with 236 people killed on average each day since the Geneva II process began, the Syrian Observatory for Human Rights said Thursday.
The ongoing evacuation of civilians from besieged rebel-held areas of Homs -- seen as the only tangible result so far of the talks -- has been hailed as a relative success.
But UN humanitarian chief Valerie Amos expressed frustration at the "extremely limited and painstakingly slow" process of getting 1,400 people out, stressing that there are "nearly 250,000 more to go if you look at all the besieged communities" in Syria.
And the UN refugee agency said 381 evacuated men and boys were still in regime hands as part of its "vetting" process.
Washington and London have demanded that Damascus honour a pledge to release the detained males, with British Foreign Secretary William Hague calling the detentions "outrageous".