Top U.S. and Russian officials for Iran have met in Vienna, a Russian envoy said on Wednesday, and delegates on both sides said Moscow and Washington were coordinating in a bid to salvage the 2015 Iran nuclear deal.

Mikhail Ulyanov, Russia's envoy to talks on the nuclear pact, wrote on Twitter that he had met twice on Wednesday with the U.S. special envoy to Iran, Robert Malley, posting pictures of himself and the U.S. diplomat sitting across from a long table.

The State Department, when asked about the meeting, said it does not discuss the details of diplomatic conversations.