Russian Foreign Minister Sergei Lavrov used pizza and vodka to have a dig at his U.S. counterpart Secretary of State John Kerry on Friday, as talks between the two veteran diplomats on Syria dragged on towards midnight in Geneva.

Lavrov made three unscheduled visits to the windowless basement ballroom of the President Wilson Hotel where journalists had been waiting for hours for news of a possible breakthrough in the talks.

On his first appearance, Lavrov made clear that the waiting reporters should blame Kerry for the delay, and expressed disbelief that things were taking so long.

"I hope before Washington goes to sleep we can get some news," he said.

An hour or so later, he fed the eager press corps another tidbit - literally. A beaming Lavrov, accompanied by a posse of officials, including one bearing a tall stack of pizza boxes, announced that they were a gift "from the U.S. delegation".

As ravenous reporters quickly polished off the pizza, Lavrov came again, this time to hand over two bottles of Russian vodka.

"Pizza from the American delegation. This is from the Russian delegation," he said.