US Secretary of State John Kerry met with his Russian opposite number on Friday and made what he said was "a little bit of progress" on resolving their differences over the Syrian crisis.
"We're evaluating some mutual ideas in a constructive way, period," Kerry told reporters at the United Nations, one day after international envoys failed to find a way to revive a US and Russian-brokered truce.
Kerry and Russia's Foreign Minister Sergei Lavrov have met several times this week in New York, including on Thursday as joint chairs of the 23-nation International Syria Support Group (ISSG).
But they have failed to agree on a way to revive the deal that they had reached in Geneva on September 9, under which Moscow would ensure its ally Bashar al-Assad honors a ceasefire and Washington would rein in Syrian rebels.
Both men are due to leave the city later Friday but there has been no sign of an agreement, with Kerry demanding that Moscow order Syria's air force to be grounded and Lavrov accusing the opposition of breaking the truce.
"I met with the foreign minister, we exchanged some ideas and we had a little bit of progress," Kerry said.
Earlier, before the meeting, Lavrov had been asked whether there was any way to revive the ceasefire. He replied simply: "You should ask the Americans."