Iranian President Masoud Pezeshkian is set to visit Moscow on Jan. 17 and sign a cooperation agreement with Russian President Vladimir Putin, Russian state news agency RIA cited Iran's ambassador to Russia as saying on Thursday.
Russia has cultivated closer ties with Iran and other countries hostile towards the US, such as North Korea, since the start of the Ukraine war.
The country's Foreign Minister Sergei Lavrov said in October that Moscow and Tehran intended to sign a deal which would include closer defense cooperation.
The United States accused Tehran in September of delivering close-range ballistic missiles to Russia for use against Ukraine, and imposed sanctions on ships and companies it said were involved in delivering Iranian weapons. Tehran denies providing Moscow with the missiles.