His election has raised hopes the landmark 2015 deal might be salvaged after the accord was largely left in tatters when the previous White House adminstration exited the agreement in 2018.

Russian Foreign Minister Sergei Lavrov said ahead of the talks in Moscow that "one of the most pressing topics is the task of rescuing the Joint Comprehensive Action Plan (JCPOA)".

Iranian Foreign Minister Mohammad Javad Zarif thanked Moscow for its efforts to repair the JCPOA after the US exit and for Russia's "constructive and principled" position on the deal.

Zarif called for continued unity between Moscow and Tehran "in order to save the JCPOA from the risks and fears that arose after the United States left this plan."

The JCPOA was agreed in 2015 between Iran, the United States, China, Russia, Britain, France and Germany.

It offered sanctions relief in exchange for curbs on Tehran's nuclear ambitions and guarantees it would not seek an atomic bomb. Iran maintains it has only pursued a civilian nuclear energy program.

The agreement largely fell apart after former US president Donald Trump unilaterally withdrew and ordered officials to reimpose tough penalties against Tehran as part of his administration's "maximum pressure" policy.