The comments come a day before Iranian Foreign Minister Abbas Araghchi is due in Moscow for talks with top Russian officials, including on the state of the US-Iran talks.

Moscow, which commands the world's largest confirmed arsenal of nuclear weapons, has deepened its military ties with Iran since it launched its offensive on Ukraine in February 2022.

"The Russian Federation remains ready to do everything within our capabilities to contribute to the settlement of the situation by political and diplomatic means," Kremlin spokesman Dmitry Peskov told reporters, responding to a question from AFP over whether Moscow would consider being a guarantor of any deal.

An Iranian MP had raised the possibility of Russia and China being joint guarantors of any future agreement in an interview with Russia's state-run RIA Novosti.

Russia has issued multiple calls for calm after US President Donald Trump last month appeared to threaten to bomb Iran if it did not engage in talks about restricting its nuclear programme.

Peskov did not say whether Russia would act as guarantor to any agreement, only that Moscow was "counting" on a second round of talks between Iran and the United States.

Iranian and US officials held indirect talks in Oman last week, the highest-level meeting between the two sides since Trump abandoned a landmark nuclear deal in 2018.

Also on Wednesday the upper house of the Russian parliament voted to ratify a strategic partnership treaty with Iran that was signed by the two countries' leaders earlier this year.