"Israeli aircraft carried out a strike targeting the road linking Syria and Lebanon" in the Quseir region on the Syrian side of the border, the Britain-based Syrian Observatory for Human Rights said.

Rami Abdel Rahman, the head of the group with a wide network of sources in Syria, said the strike came as part of Israeli attempts "to cut the supply line to Hezbollah".

There were no casualties and it was not immediately clear if the road had been cut off in the strike, he said.

Lebanon's National News Agency reported "enemy drone strikes on the border between Lebanon and Syria".

The strike comes less than a week after Israeli jets struck the main Lebanon-Syria border crossing of Masnaa in Lebanon's eastern Bekaa Valley, cutting off the road to traffic.

The Israeli military said its jets Friday struck Lebanese militant Hezbollah positions near the border.

Human Right Watch on Monday said the strikes near the main Lebanon-Syria border crossing were putting civilians at "grave risk" as they prevented them from fleeing and hampered humanitarian operations.

Increased Israeli air strikes against Hezbollah in Lebanon have killed more than 1,200 people and displaced over a million from their homes, according to official figures.

More than 400,000 people -- mostly Syrians -- who have fled over the frontier into Syria.