Russian President Dmitry Medvedev will meet Mahmoud Ahmadinejad this week in the wake of the Iranian leader's disputed re-election, a top Kremlin official said on Sunday.
Medvedev is also to hold a three-party meeting with Afghan President Hamid Karzai and Pakistani President Asif Ali Zardari, said Sergei Prikhodko, the Russian leader's top foreign policy advisor.
The meetings will take place on the sidelines of two summits being held on Monday and Tuesday in Russia, a key Iranian ally.
Medvedev and the Iranian president will discuss "issues related to Iran's nuclear program and the need to further expand cooperation with the International Atomic Energy Agency," the UN's atomic watchdog, said Prikhodko.
The talks will also include "the situation around Iraq and in the Middle East as a whole," he told a news briefing at the Kremlin.
Ahmadinejad defended his hotly disputed re-election win at a huge rally on Sunday after security forces cracked down on opposition protestors with mass arrests.
On Monday, Russia will host a summit of the Shanghai Cooperation Organisation (SCO), a regional group dominated by Russia and China that also includes Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan.
Leaders from the BRIC group of emerging economies, which includes Russia, Brazil and India, will meet the following day.
The Russia-led SCO is ready for closer cooperation with the United States on Afghanistan, Prikhodko said.
"The niches of cooperation between the SCO with Western countries, including the US, can be expanded," he said.
Cooperation would however be limited to reconstruction of the war-torn country and the transit of supplies, he said, adding there had been "an increased transparency" of the US strategy in Afghanistan and Pakistan.
"We are ready to closely cooperate, coordinate our efforts on the Afghan track with other international organisations: the United Nations, the CSTO, NATO, the European Union," Prikhodko said.
CSTO is the Collective Security Treaty Organisation, a regional grouping that Moscow has touted as a counterweight to NATO and includes Belarus, Armenia, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan.
Earlier this year, Russia allowed the US to send a first trainload of non-lethal supplies across its territory for the operation in Afghanistan, where Western forces have been struggling to contain a Taliban insurgency.