According to information from Russian military intelligence, IS was planning a major attack on a strategically important city of Deir ez-Zor. Russian Defense Ministry said that Russian air force conducted preemptive strikes to thwart the attack on the city.
Russian airstrikes left some 180 IS fighters dead, including two commanders.
Russian surveillance drones in Syria noticed the concentration of ISIS forces near the besieged Syrian city, Russian Defense Ministry said in a statement on Saturday.
The two IS commanders killed in the attacks Belgian Abu Umar al-Beljiki and Egyptian Abu Yasin al-Masri, both prominent field commanders. The Russian ministry also said that 18 of IS vehicles were destroyed in the attack. In addition, IS lost an artillery piece and an ammunition stockpile.
Earlier this week, Russian Defense Ministry released satellite images of an are hit by Russian-led airstrike which may have killed IS leader Abu Bakr al-Baghdadi, but the information is yet to be confirmed.
Syrian government forces, with support from Russia and various Shia militias, have managed to reclaim significant portion of Syrian territory from IS, but large areas in the east of the country still remain under IS control.
Deir ez-Zor is the largest city in eastern Syria, and occupies a strategically important position on the Euphrates River. Recently, Syrian army forces and Hezbollah have liberated the area near the city.