Beirut: Syrian forces crossed into Lebanon and shot dead a Syrian man in the eastern Bekaa Valley, security sources said on Friday.

They said the shooting occurred on Thursday as the Syrian soldiers were pursuing Ali Al Khatib near the village of Arslan, where Syrian forces made a similar incursion two days earlier.

The frontier between the two countries is poorly delineated in some of the remote border areas, which are havens for smugglers bringing subsidised Syrian goods into Lebanon or arms across into Syria.

Lebanon's army did not comment on the incident.

Syrian security forces have been cracking down on six months of protests against President Bashar Al Assad. The United Nations says 2,900 people have been killed and at least 3,800 Syrians have taken refuge in Lebanon.

Syrian authorities blame armed groups backed by foreign powers for the violence, and say they have caught large quantities of weapons being smuggled into the country.