Looking across the border from the Lebanese village of Boqaya, Syrian soldiers could be seen deploying along a stream in Arida village and entering homes. Lebanese soldiers fanned out on their side of the frontier.

Earlier, sporadic gunfire and shelling were heard from the village. Arida is near the town of Tel Kelakh, where one rights activist says Syrian troops have killed at least 27 civilians since entering it on Saturday. On Thursday a resident said that armored personnel carriers and dozens of buses filled with soldiers had begun pulling out of Tel Kelakh around noon and were heading north.

Syrian security forces have used tanks, gunfire and mass arrests to crack down on flashpoints in an attempt to crush a two-month-old revolt against four decades of authoritarian rule by the Assad family. The United States on Wednesday froze any assets belonging to President Bashar Assad and six senior Syrian officials that fall within US jurisdiction.

Damascus condemned the sanctions, saying they targeted the Syrian people and served Israel's interests. "The sanctions have not and will not affect Syria's independent will," an official source was quoted as saying on state television.