Updated

Lebanese officials and a Syrian activist group say heavy clashes along the Syria-Lebanon border have killed several people, including a number of Hezbollah fighters.

Syrian troops backed by Hezbollah militants have been on the offensive in Syria's mountainous Qalamoun region since November, trying to clear the area of rebels.

Officials in eastern Lebanon say the clashes broke out on Sunday after Syrian rebels tried to infiltrate into Lebanon and clashed with Hezbollah fighters. The officials spoke on condition of anonymity in line with regulations.

They say the fighting, which took place near the Lebanese village of Youneen, ended at dawn on Monday after Hezbollah took control of the nearby hills. Several militants were killed.

The Britain-based Syrian Observatory for Human Rights says there were casualties on both sides.