There was no immediate claim of responsibility but both the Syrian Observatory for Human Rights, a U.K.-based opposition war monitor, and the pro-government radio station Sham FM said IS was behind the attack.
Both the Observatory and Sham FM said 22 fighters were killed. Sham FM said they were all Quds Brigade gunmen, while the Observatory said the majority belonged to the group.
The Quds Brigade fought on the side of Syrian government forces during the country’s 13-year conflict, which has killed half a million people and displaced half the country’s pre-war population of 23 million.
The Quds Brigade is different from the military wing of the Palestinian Islamic Jihad group, which uses the same name.
Despite their defeat in Syria in March 2019, IS sleeper cells have been blamed for deadly attacks against both Syrian government forces and against members of the U.S.-backed and Kurdish-led Syrian Democratic Forces.