Tu-22M3 long-range bombers and Su-34 tactical bombers took off from Hamedan airbase in western Iran Tuesday, and hit targets belonging to ISIS and the Jabhat al-Nusra militant group in the Syrian provinces of Aleppo, Deir Ezzor and Idlib, Russia's defense ministry said in a statement.
The raids "eliminated" five major arms depots, used to supply ISIS militants near the city of Aleppo, as well as three militant command points and training camps in the cities of Serakab, Al-Bab, Aleppo and Deir Ezzor.
A "significant number of militants" were also thought to be killed, the ministry said.
All Russian aircraft returned to their home airfields safely after a successful "combat mission," the statement added.
Tehran and Moscow "enjoy strategic cooperation in the fight against terrorism in Syria and share their facilities and capacities to this end," Iran's Secretary of Supreme National Security Council Ali Shamkhani said Tuesday in an interview with Islamic Republic News Agency (IRNA).
Russia airstrikes have played a key role in allowing regime forces under President Bashar al-Assad to retake territory lost to ISIS and other rebel groups across Syria.
Though Russia insists it has been targeting ISIS forces, the majority of its airstrikes have been against US-backed rebels battling Assad's forces, according to Washington.
US Secretary of State John Kerry recently threatened a "Plan B"
to increase arms to Syrian rebels if Russia and Assad did not change tactics and stop targeting moderate opposition groups supported by the US and its European and Arab partners.
And airstrikes have been taking the toll on war-torn cities like Aleppo -- creating what CNN's Clarissa Ward described as an "apocalyptic wasteland." Hundreds of thousands of civilians were recently caught up in a siege
of parts of Aleppo, preventing vital aid supplies from getting through.
In response, Moscow announced the creation of a "humanitarian corridor" in the city for three hours a day.