Iranian President Hassan Rohani is in Moscow for talks with top Russian leaders aimed at bolstering relations between the two allies.
Rohani met with Prime Minister Dmitry Medvedev on March 27 and was expected to meet with President Vladimir Putin the following day.
It is expected to be Rohani's last foreign trip before Iran's May 19 presidential election.
"I would like to express my confidence that your visit will open a new page in Russian-Iranian cooperation," Medvedev said at a joint press conference.
The talks were expected to center on Russian arms supplies to Tehran and on Russian investment in Iran's energy sector.
In all, about a dozen memorandums of understanding were expected to be signed during the visit.
Iran's relations with the United States have been particularly strained since Tehran conducted a ballistic-missile test in January, prompting U.S. President Donald Trump to put the country "on notice" and to move forward with fresh sanctions.