The United States and Russia are to chair a meeting in New York on Thursday bringing together world powers with a stake in Syria's civil war, officials told AFP.

The 23-nation International Syria Support Group (ISSG) was set up to push for a ceasefire and an eventual political resolution to the bloody five-year-old conflict.

A US official confirmed a meeting was being set up, and diplomats said it would take place at 2 pm (1800 GMT) in a New York hotel. 

Foreign ministers, already gathered in New York for the UN General Assembly, held an emergency meeting of the ISSG on Tuesday after a week-old truce broke down.

But they made little progress amid bitter recriminations between the ISSG co-chairs, US Secretary of State John Kerry and Russia's Foreign Minister Sergei Lavrov.

Washington blames Russia for carrying out a deadly air strike on a UN aid convoy in northern Syria after Bashar al-Assad's military declared the ceasefire over.

Moscow denies any role in the attack and in turn accuses US leaders of failing to ensure that the US-backed opposition forces fighting Assad respected the truce.

Kerry and Lavrov sparred bitterly in the UN Security Council on Wednesday, but ministers agree the US-Russian effort is the only way available to impose a ceasefire.

Kerry has demanded that Russia order Assad to ground his air force in order to re-establish the credibility of the peace effort in the eyes of the suspicious opposition.

Lavrov has countered that the UN Security Council should consider adding some more of the anti-Assad rebel groups to its list of proscribed terrorist organizations.

Asked whether the ceasefire could be salvaged, Kerry said he would meet with Lavrov once again to try to narrow their differences.

But he added: "It's going to be very difficult. We'll see what people are willing to do."

If either side is able to come up with concrete measures to restore the truce, they could be endorsed by the ISSG at the meeting and the peace process would continue.

Failing 'that, Kerry has admitted that Syria's future is "hanging by a thread."      

Source: AFP