ARSAL, Lebanon: Two Syrian warplanes bombed farm fields in a Lebanese town near the border with Syria Monday, senior Lebanese security sources said, in the first airstrike targeting Lebanese territory since the uprising in Syria began 18 months ago.

Two MiG jets fired three missiles on the farm fields of Khirbet Dawoud, about five kilometers northeast of Arsal, causing no casualties but material damage to farmhouses, the sources told The Daily Star.

Following the air raid, Syrian reconnaissance planes and helicopters flew briefly over the area, while the Lebanese Army rushed to the site of the attack, which occurred at 10:30 a.m., the sources said.

Khirbet Dawoud, an agricultural land, is part of the Arsal region that shares 50 km of border with Syria. The area is also alleged to be the main point for arms smuggling between Arsal and Syrian territory.

President Michel Sleiman has asked Defense Minister Fayez Ghosn to investigate the attack.

“An attack occurred today on Khirbet Dawoud in the border Arsal region. Investigation is still ongoing in this regard to take the necessary measures,” Sleiman told a Cabinet session he chaired at Baabda Palace.

“We have to always be in contact with Syrian officials as part of our duty in protecting Lebanese citizens,” Sleiman added.

Speaking to The Daily Star, Ahmad Fliti, deputy head of Arsal’s municipality, said he believed that the air raid was in response to a military attack carried out by members of the rebel Free Syrian Army on a Syrian border guard post that resulted in the killing of five to 12 guards.

The Syrian forces were believed to be chasing rebels in the area, which has been the site of clashes in the past between opposition fighters battling Syrian troops just on the other side of the frontier.

Syrian shells have hit Lebanese territory in the past, but Monday’s air raid appears to be the most serious violation.

Several Lebanese, including a TV cameraman, have been killed and dozens wounded by fire coming from the Syrian side.

After last month’s attacks on villages that wounded a Lebanese soldier, Prime Minister Najib Mikati instructed Lebanon’s ambassador to Syria to send a letter of complaint to Syria’s Foreign Ministry about “the continuous shelling of Lebanese border towns from nearby Syrian military bases.”

Commenting on the Syrian raid, Kataeb Party MP Sami Gemayel called on the Army to swiftly respond to any Syrian shelling of Lebanese territory.

“It is not acceptable for the Army to stand idle regarding such violations against Lebanese territories and the people without doing anything about them,” he said at a news conference.

“We ask the Army to immediately respond to any Syrian shelling. It is its national duty to defend the land.”

The opposition March 14 bloc has called for U.N. peacekeepers to be deployed along the border with Syria.