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MOSCOW — Russian bombers took off from a base in Iran to conduct airstrikes in against ISIS in Syria on Tuesday, officials said, marking a new development in the country’s civil war.

It was the first time Russia used the territory of another Middle Eastern country for its operations inside Syria in support of President Bashar Assad.

An image provided by Russia's defense ministry shows a Russian Tu-22M3 bomber over Aleppo, Syria, on Tuesday. AP

Russia’s defense ministry said Tu-22M3 and Su-34 bombers took off on raids targeting ISIS and allied Nusra Front militants in Aleppo, Deir el-Zor and Idlib — destroying five major ammunition depots, training camps and three command posts.

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The airstrikes also hit “numerous militants,” it said in a statement.

The jets took off “with a full bomb load” from the Hamadan base and were protected by Su-30sm and Su-35s military airplanes, the statement added.

Iran’s state-run news agency IRNA on Tuesday quoted Ali Shamkhani, the secretary of Iran's Supreme National Security Council, as saying that Tehran and Moscow will share “facilities and capacities” in the fight against ISIS.

Moscow and Tehran are the main international backers of Assad, with Russia supporting the regime's forces with airstrikes, and Iran with ground troops.

Russia, Iran, Iraq and Syria also have set up a joint center in Baghdad with the goal of coordinating the campaign against ISIS.

Russian President Vladimir Putin met with his Iranian counterpart Hassan Rouhani last week, though neither made any mention of a possible deal on Iranian air bases.

Tuesday's announcement came a day after Russia's defense minister said Moscow and Washington were edging closer to an agreement on Syria that would help defuse the situation in the besieged city of Aleppo.

Sergei Shoigu said the agreement would "allow us to find common ground and start fighting together for bringing peace to that territory," according to The Associated Press. He said Russian representatives are "in a very active stage of talks with our American colleagues.”

Russia and the United States have been discussing greater coordination for striking extremists in Syria, but have been unable to reach agreement on which militant groups could be targeted.

The U.K-based Syria Observatory for Human Rights said at least 20 civilians – including three children – had been killed in airstrikes on districts of Aleppo Tuesday, although it was not clear if Russian or Syrian planes were responsible.