Islamic State fighters killed at least 37 rival insurgents in an overnight attack in Syria's Aleppo province and 20 fighters remain missing, the Syrian Observatory for Human Rights said on Sunday.
Rami Abdulrahman, head of the Observatory, said that late on Saturday a suicide bomber from the hardline group blew himself up in a military post held by a group of rival insurgents in the Umm Housh village in northern Aleppo countryside.
Islamic State fighters then seized the village after heavy clashes with rival groups.
"The main goal for taking the village is to tighten the noose around Marea which is considered a reservoir for groups that are against the Islamic State," Abdulrahman said.
Jihadi groups and Islamist and mainstream groups have been engaged in internecine fighting for more than two years, complicating the four-year conflict in Syria.