DAMASCUS, Jan. 19 (Xinhua) -- At least 20 Islamic State (IS) militants were killed in eastern Syria on Saturday by Iraqi airstrikes and shellings from pro-government fighters, a war monitor group reported.

The Iraqi warplanes and the pro-Syrian government fighters targeted the last IS-held pocket on the eastern bank of the Euphrates River in eastern Syria, according to the Syrian Observatory for Human Rights.

The shellings and airstrikes were coupled with clashes between IS militants and the Kurdish-led Syrian Democratic Forces (SDF) on the ground.

The Britain-based watchdog group said a total of 1,159 IS militants have been killed since the SDF launched their offensive in the eastern Euphrates region on Sept. 10, 2018.

A total of 626 SDF fighters and 373 civilians in that area were killed during the fightings, according to the monitor group.

The SDF and Syrian Army are fighting IS, which is still holding two towns in the eastern Euphrates region, separately.