The Russian Defense Ministry said that the Tu-22M3 long-range bombers took off from an airfield in Russia and flew over the territory of Iraq and Iran.
"On January 23, 2017, six long-range Tu-22M3 bombers that took off from a Russian airfield and flew over Iraq and Iran carried out airstrikes on Daesh's command posts, arms and ammunition depots near Deir Ez-Zor populated area."
The ministry added that all targets have been destroyed.
"Su-30SM and Su-35S provided air cover to the Russian bombers from the Hmeymim airbase."
After successfully completing their combat mission in Syria, the Russian jets returned to Russia.
On Saturday, Russian strategic bombers also targeted Daesh positions in Deir ez-Zor.
Commenting on the development of the situation in the area, the Russian General Staff said on Wednesday that if terrorists capture Deir ez-Zor, civilians will be subjected to genocide and the population may be completely exterminated.
The city of Deir ez-Zor, which is still held by Syrian government forces, has been under Daesh's siege since July 2014. The residents of Deir ez-Zor and the servicemen receive food only via planes delivering humanitarian aid.