Moscow (AFP) - Russian President Vladimir Putin will visit Iran later this month, the Kremlin said Friday, with the two countries backing Bashar al-Assad in Syria and Moscow looking to step up business ties after the deal over Tehran's nuclear programme.

Putin -- who last visited Iran in 2007 -- will head to Tehran for a forum of gas-exporting countries on November 23 and is expected to hold talks with the Iranian leadership, the Kremlin's top foreign policy aide Yury Ushakov said.

"It is entirely logical that some bilateral contacts are envisioned, including with the hosts," Ushakov told journalists, without specifying what would be discussed.

Russia and Iran are the key military supporters of Assad's forces on the ground in Syria, with Moscow conducting a bombing campaign and Iran believed to command thousands of fighters in the country.

International powers are also currently engaged in their broadest diplomatic push yet to resolve the nearly five-year conflict that has killed some 250,000 people.

Around 20 countries and international bodies will meet in the Austrian capital Vienna on Saturday to try to push forward a peace plan that would include a ceasefire between the regime and some opposition groups, and talks to find a political solution

Russia and Iran have clashed with the US and its regional allies such as Saudi Arabia and Turkey over if and when Assad should leave power.

The visit to Iran also comes as Russia is looking to bolster business ties with the country after Tehran inked a landmark deal in July to curb its nuclear ambitions that should see a raft of international sanctions lifted.

Moscow has already angered the US and Israel by reviving an agreement to deliver S-300 missile systems to Iran, after suspending the deal in 2010 over United Nations sanctions.

Moscow is also looking to use its long-standing ties with Tehran to win lucrative contracts in the energy sector with a host of other countries also looking to muscle in.