Top diplomats from Russia, the US, Saudi Arabia and Turkey on Friday failed to make any major breakthrough on how to end the Syrian conflict, with the sides sharply at odds on the future of Bashar al-Assad.
But Moscow did seem to make progress with getting some more regional players on side, announcing with Jordan that the two countries would begin to "coordinate" their air operations over Syria.
US Secretary of State John Kerry, meanwhile, said he hoped to reconvene another, "broader" meeting on Syria as early as October 30.
The crunch talks at a Vienna hotel brought together Kerry and Russian Foreign Minister Sergei Lavrov with their Saudi counterpart Adel al-Jubeir and Turkey's Feridun Sinirlioglu.
The foreign ministers met three weeks after Moscow thrust itself into the heart of the crisis by launching a bombing campaign in support of Assad that has drawn sharp condemnation from the west.
Washington, Riyadh and Ankara -- which all back groups fighting Assad -- were sounding out Lavrov after the embattled Syrian strongman made a surprise visit to Moscow to meet President Vladimir Putin this week.
But the atmosphere appeared frosty, and there was scant progress on resolving almost five years of war with the sides at loggerheads over the future of Assad.
"What we agreed to do today is to consult with all parties and aim to reconvene, hopefully as early as next Friday with a broader meeting in order to explore whether there is sufficient common ground to advance a meaningful political process," Kerry told journalists after the meeting.
- Iran 'not at the table' -
Lavrov said Moscow wanted the negotiating group to be expanded to include key international and regional players including crucially Iran -- which is also backing Assad's forces on the ground.
But Kerry rejected the suggestion of involving Tehran for now.
"For the moment Iran is not at the table. And there will come a time perhaps where we will talk to Iran but we are not at the moment at this point of time," he said.
Another bone of contention appeared to be the fate of Assad, with Kerry insisting "dozens of countries, if not hundred, understand that Assad creates an impossible dynamic for peace".
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Lavrov, however, struck out at the "fixation" with Assad among the other participants and said "the fate of the president of Syria must be decided by the Syrian people".
On September 30, Russia launched a bombing campaign in Syria, which has shifted the dynamics of the brutal four-and-a-half year war -- allowing Assad's battle-weary forces to go on the offensive and overshadowing a US-led coalition bombing the Islamic State (IS) group.
The US and its regional allies have decried Russia's strikes, insisting Moscow is not focusing on IS as it claims, but on other groups fighting Damascus, and that the Kremlin's intervention will only prolong the bloodshed.
Russia has been frantically trying to get the US and its coalition partners to cooperate with its bombing campaign in Syria, and Putin on Thursday stressed the need for "joint work" to defeat "terrorism" in Syria.
- Cooperation with Jordan -
In a potential step forward, Lavrov announced that Russia and Jordan -- another member of the US-led coalition -- had agreed to "coordinate" their military actions in Syria and set up a "mechanism" to facilitate that end after meeting his Jordanian counterpart separately.
While the scope of the coordination was not clear, it appears to outstrip the limited understandings Russia has with Israel and the US to avoid accidental air collisions over Syria.
"I hope this mechanism will be effective in fighting all terrorism in Syria and beyond," Jordanian Foreign Minister Nasser Judeh said at a joint press conference with Lavrov.
Later Lavrov said that he hoped other countries would participate in the initiative in the Jordanian capital and that if the US-led coalition shared intelligence then Russia could help "patriotic opposition" groups fight IS.
"It is also important to agree not only the targets of the adversary, our common enemy -- terrorism -- but to also agree on those areas that are being controlled by the patriotic opposition so that we could also help it fight IS," Lavrov said, without specifying which group Moscow deems the "patriotic opposition".
As the talks were under way in Vienna, IS jihadists cut off a key regime supply route between Syria's provinces of Aleppo and Homs despite Moscow's air strikes, the Syrian Observatory for Human Rights said Friday.
While the Syrian conflict dominated the Vienna talks, Lavrov and Kerry also discussed the latest Israeli-Palestinian violence with representatives from the European Union and United Nations.
The talks were part of a flurry of diplomatic activity to end more than three weeks of bloodshed which has raised fears of a new Palestinian intifada, or uprising.