Lebanese security official told the Associated Press that two 107 mm rockets were launched using timers from an area between the villages of Adaisseh and Kfar Kila, a few miles from Israel’s border. The official spoke on condition of anonymity because he was not authorized to talk to the media.

The Lebanese army said in a statement three 107 millimeter Katyusha rockets were fired at Israel by "unknown elements" and that a search was underway to find the attackers. Troops sent to search the suspected launching area found a fourth rocket equipped with a timer.

Israeli Channel 2 TV’s Arab affairs analyst, Ehud Yaari, said a splinter Palestinian group in Lebanon was probably behind the attack. There was no claim of responsibility.

In the past, small Palestinian groups, like the Popular Front for the Liberation of Palestine, have fired a few rockets at Israel.

Yasmina Bouziane, a spokeswoman for the U.N. Interim Force in Lebanon, said the rocket attack was considered a "serious breach of cessation of hostilities agreement" from last year’s war.

UNIFIL and Lebanese troops have intensified patrols of the area "in order to locate the perpetrators and prevent any further attacks," she added.

The peacekeeping force urged the parties to exercise maximum restraint to prevent escalation.

Late Sunday, a drone aircraft could be heard circling over the southern Lebanon port city of Tyre, witnesses said. UNIFIL and the Lebanese army have no drones, and Israel has frequently flown such small aircraft to monitor movements on the ground in southern Lebanon.