Iranian President Hassan Rohani is to begin a two-day visit to Russia on March 27 where he is due to meet with President Vladimir Putin and Prime Minister Dmitry Medvedev.
Rohani said before flying to Moscow that he welcomes Russian investment in Iranian gas and oil fields.
"There is a huge potential for Russian investment in Iran's energy sector," said Rohani. "Some oil and gas fields have been suggested to Russian companies. ... We will see a big development in energy cooperation."
Rohani's trip comes ahead of the May 19 presidential election, in which Rohani is seeking reelection.
A Russian government official said the Iranian and Russian leaders will discuss trade, the economy, and energy during the visit.
The agenda is certain to include international geopolitics and the civil war in Syria, in which Russia and Iran support Syrian President Bashar al-Assad's government forces in their fight against opposition forces backed mainly by Turkey and a U.S.-led coalition.
"The visit shows the importance that Russia has in Iranian foreign policy," Mohsen Milani, author of The Making Of Iran’s Islamic Revolution: From Monarchy To Islamic Republic, told The Washington Post.
The Iranians are "playing a key role in Putin’s longer-term strategy to become a major player in the Middle East," he added.
Rohani is scheduled to begin his visit by meeting Medvedev on March 27, officials said.