BEIRUT (AP) — A Syrian activist group says fighting in northern Syria the previous day killed several fighters belonging to the Lebanese militant Hezbollah group.

Hezbollah has been fighting alongside President Bashar Assad's troops in Syria's civil war.

The Britain-based Syrian Observatory for Human Rights says 12 Hezbollah fighters were killed and dozens were wounded in Saturday's attack by militants led by al-Qaida's Syria branch — known as the Nusra Front — on the northern village of al-Ais.

In southern Lebanon, social media postings on Sunday carried photos of seven Hezbollah fighters said to be among those killed in al-Ais.

Though Nusra Front is not part of a U.S.-Russia-engineered truce between the Syrian government forces and Western-backed rebels, the fighting has threated to undermine the cease-fire that has held for over a month.