With Syria's cease-fire in shambles, the United States and Russia are preparing to butt heads once again over ways to revive it.
Amid widespread disagreement today between Washington and Moscow and internal dissent within the Obama administration over how or even if to proceed, Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov convened what diplomats expected to be a fractious meeting of the roughly 20 nations that have declared interests in Syria.
The International Syria Support Group was to consider a US call for all warplanes to halt flights over aid routes following an attack on a humanitarian convoy near the besieged city of Aleppo, as well as a Russian suggestion for a three-day pause in fighting to get the "cessation of hostilities" back on track.
However, diplomats said prospects for the success of either idea were unclear.
Syrian President Bashar Assad told the AP in an interview in Damascus that the United States was to blame for the deal's failure.
Kerry's proposal to halt all flights was met with disagreement both in Moscow and even in Washington.
The top US military official told Congress he thought grounding all warplanes was a bad idea and Russia's deputy foreign minister said grounding the flights would make matters worse.
Attack on aid convoy
Assad told The Associated Press that the US lacked "the will" to join forces with Russia in fighting extremists and rejected Washington's claim that an errant US airstrike last week that killed 62 Syrian troops was accidental.
The opposed views of Washington and Moscow were on full display at a UN Security Council meeting yesterday that had originally been called to enshrine the truce.
Instead, members rued the possibility of a darker phase in the conflict amid increased attacks on humanitarian workers.
And, in unusually blunt language, they illustrated why they've been unable for more than five years to stop Syria's civil war.
While the US and Russia have previously jousted over proposed resolutions critical of the Syrian government, yesterday's agenda didn't even include a suggested course of action.
Instead, the two-hour discussion served as a warm-up act for today's meeting.
Kerry blamed Russia, lambasting what he portrayed as a cynical response to an airstrike on a humanitarian aid convoy this week that killed 20 civilians and raised "profound doubt" about Russia's and Syria's willingness to abide by the cease-fire.
The US believes that a Russian-piloted aircraft carried out the strike, said a senior American official, who wasn't authorised to speak publicly on the matter and demanded anonymity.
Russia has denied US claims that it was responsible, but Kerry focused on its shifting explanation of what might have happened.