Russia has carried out an airstrike against ISIS-controlled eastern Syria using Su-34 bombers, the Ministry of Defence of the Russian Federation has revealed.

The Russian bombers took off from Hamedan airbase in Iran with full fragmentation bomb charge to launch an airstrike against ISIS facilities in Syria's Deir ez-Zor province.

As a result of the strike, more than 150 militants including foreign mercenaries were killed.

Russia has used the Iranian base to bomb Syrian militants for the first time.

The Syrian Observatory for Human Rights (SOHR) said that 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 supporting President Bashar Assad’s government for nearly a year.

Russia has also sent Tu-22M3 bombers to target ISIS and the Nusra Front militants in Aleppo, as well as in Deir ez-Zor and Idlib.

"Russia has used the Iranian base to bomb Syrian militants for the first time."

The strikes destroyed five major ammunition depots, training camps and three command posts in total.

The strikes by Russian warplanes on Tuesday follows an announcement that Moscow and Washington are nearing an agreement on Syria that would help defuse the situation in the besieged northern city of Aleppo, SOHR said in a statement.

SOHR said that Russia and Iran have been expanding their ties in past months after most of the sanctions against Iran were lifted following a nuclear deal with world powers.

Image: Russian Su-34 bombers in flight. Photo: courtesy of the Ministry of Defence of the Russian Federation.