Russia's Defense Ministry says that Russian warplanes have taken off from a base in Iran to target Islamic State fighters in Syria.

Moscow: Russian warplanes took off on Tuesday from a base in Iran to target Islamic State fighters and other militants in Syria, Russia's defence ministry said, marking a major development in the country's civil war, now in its sixth year.

Russia has never used the territory of another country in the Middle East for its operations inside Syria, where it has been carrying out an aerial campaign in support of President Bashar Assad's government for nearly a year. The announcement suggests cooperation on the highest levels between Moscow and Tehran, both key allies of the embattled president.

It comes a day after Russia's defense minister said Moscow and Washington are edging closer to an agreement on Syria that would help defuse the situation in the besieged northern city of Aleppo.

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

A US official said, however, that discussions with the Russians are still ongoing and no agreement is close. The official spoke on condition of anonymity because of the sensitivity of the talks.

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

Russia has criticised what it describes as US reluctance to persuade the Syrian opposition groups it supports to withdraw from areas controlled by Al-Qaeda's branch in Syria.

The Russian ministry's statement issued said Su-34 and Tu-22M3 bombers took off earlier in the day to target Islamic State and the Nusra Front militants in Aleppo, as well as in Deir el-Zour and Idlib, destroying five major ammunition depots, training camps and three command posts.

Nusra Front is Al-Qaeda's branch in Syria. However, the group recently announced it was changing its name to Fath al-Sham and severing ties with the global terror network in an apparent attempt to evade Russian and US-led airstrikes. Russia and the US have dismissed the name change as window-dressing.

The Russian defence ministry released a video showing a Russian Tu-22M3 long-range bomber dropping bombs in strikes described as "terrorist objects in Syria."

Russia and Iran have been expanding their ties in the past months after most of the sanctions against Iran were lifted following the nuclear deal with world powers that put restricted Iran's nuclear program from weapons-grade capability.