BEIRUT (AP) — Syrian insurgent groups have launched a counteroffensive against government forces advancing toward a major rebel-held air base in the country's northwest, capturing several villages and taking prisoners.

The counteroffensive by several factions, including the al-Qaida-linked Levant Liberation Committee, started overnight. By Thursday morning, it slowed down the government push toward the Abu Zuhour air base that has been held by rebels since 2015.

The ultraconservative Ahrar al-Sham group says its fighters, along with other militants, have retaken the villages of Hasyan and Atshan on the southern edge of Idlib province.

The Britain-based Syrian Observatory for Human confirms insurgents have taken several villages. It says 11 pro-government fighters were captured.

The Observatory's chief Rami Abdurrahman says 16 insurgents were killed in the fighting but didn't have a figure for government troops.