The United States and Russia are taking their differences over the conflict in Syria to new heights, after trading ferocious allegations of duplicity and malfeasance at the United Nations Security Council.

After a fractious meeting of the council on Wednesday, US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov met again over Syria at a gathering of the roughly 20 nations that have an interest in Syria. Thursday's meeting of the International Syria Support Group came after the two men blamed each other for spoiling the country's cease-fire that they had agreed to earlier this month. Each has blamed the other for violations.

Kerry called for all warplanes to halt flights over aid routes, while Lavrov suggested a possible three-day pause in fighting to get the truce back on track.