Russian President Vladimir Putin is in Iran for his second foreign trip since he launched the invasion of Ukraine in February.
Mr Putin is holding meetings with Iran’s president and supreme leader, as well as Turkish President Recep Tayyip Erdogan.
Grain exports, Syria and the Ukraine conflict are on the agenda.
The visit is a chance to deepen ties with Iran, one of Russia’s few remaining international allies.
It follows allegations by US officials last week that Tehran was planning to supply Russia with hundreds of drones for its war in Ukraine.
On Tuesday, the Russian energy giant Gazprom signed a new development deal worth $40m with Iran’s state oil company.
Following his meeting with Iran’s President Ebrahim Raisi, Mr Putin said relations between the two countries were “developing at a good pace”.