JERUSALEM — Four rockets were fired toward northern Israel from southern Lebanon on Thursday for the first time in nearly two years, according to the Israeli military. The rocket fire set off sirens in the western Galilee and raised tensions in the region against the background of the conflict in Syria.

On Friday, Israeli warplanes hit a site south of Beirut in response to the rocket attack, according to The Associated Press.

The military said that Israeli planes targeted “a terror site located between Beirut and Sidon,” the news agency reported.

Ramez Mustafa, a Lebanon-based official with the Popular Front for the Liberation of Palestine, said the airstrike occurred at 4 a.m. and caused no casualties. He said the warplanes struck the coastal town of Naameh, 10 miles south of Beirut, where the Palestinian group operates.