Russia and Iran agreed to closer military cooperation, in a move announced during President Masoud Pezeshkian's visit to Moscow.
The two countries signed a 20-year “strategic partnership” treaty, covering areas ranging from defense and technology to energy and trade.
Iran is already supplying Russia with drones, as well as ballistic missiles, according to Western intelligence.
Russia has forged closer ties with Iran, along with China and North Korea, since its all-out invasion of Ukraine began in February 2022.
In the treaty, Russia and Iran pledged to consult and cooperate to deal with military and security threats, as well as to participate in joint military exercises on their territories and abroad.
They also agreed not to allow their lands to be used for actions that threaten the other side.
Iranian President Pezeshkian said that signing the agreement means that Russia and Iran are entering a new chapter in relations.
Trade between the two countries could be significantly enhanced through further cooperation in the energy sector.
During a joint press conference with his Iranian counterpart, Russian President Vladimir Putin said that his country is studying building new nuclear energy units in Iran.
Moscow is also seeking to sell some of its surplus gas to Tehran. Since the beginning of the war in Ukraine, the European Union has significantly reduced gas imports from Russia, prompting Moscow to contract new customers.
The planned gas pipeline from Russia to Iran, which the countries are negotiating, will be extended through the territory of Azerbaijan if it is implemented, Interfax news agency reported on Friday, citing Russian Energy Minister Sergei Tsevilev.
Putin said Russia could eventually supply Iran with up to 55 billion cubic meters of gas annually.
