Deputy Russian foreign minister Sergei Ryabkov met his Iranian counterpart Abbas Araghchi in Tehran where the two sides "agreed to continue close coordination in this area," the ministry said in a statement.

"The Russian side highlighted its commitment to preserving the agreement," the statement added.

Russian President Vladimir Putin on Wednesday expressed his "deep concern" over Donald Trump's withdrawal from the 2015 deal.

Earlier in the day Ryabkov said Russia's "European partners" should also work to keep the deal together, in comments reported by news agencies.

Russia's Foreign Minister Sergei Lavrov on Thursday called on countries that oversaw the deal to "develop steps that would preserve this document that is important for regional stability".

"We agree to make the appropriate contacts with our German colleagues," he said in a joint press conference with his German counterpart Heiko Maas.