As Israeli officials warned of dire consequences if Lebanon is used as a "springboard" for further attacks by pro-Syrian groups, Beirut filed a letter of complaint to the Security Council.

On Monday night, Israeli jets bombed suspected positions of the Popular Front for the Liberation of Palestine-General Command in Naameh, 20km south of the Lebanese capital.

The raid, which the PFLP-GC said had inflicted no casualties, was in response to an attack earlier Monday that Israel said targeted one of its naval vessels patrolling in Israeli territorial waters.

The raid on Naameh was the first air strike so close to the capital since the Israeli troop pullout from southern Lebanon in May 2000 after 22 years of occupation.

As part of ongoing confrontations since then, Israel raided southern and eastern Lebanon, and also carried out a single strike near Damascus in October after a suicide attack near Haifa claimed by Palestinian militant group Islamic Jihad.

The raid on Syria was the first since 1974.

Syria is the main power broker in Lebanon, and hosts the headquarters of hardline Palestinian factions which oppose the Israeli-Palestinian peace process.

Beirut newspapers wondered Tuesday about the timing of the "surprise tensions."

The leading An Nahar ran a headline reading: "Mysterious missiles by day, raid on Naameh by night."

President Emile Lahoud denounced the raid as "another violation of Lebanese sovereignty and part of the hostile Israeli practices against Lebanon," an official statement said.

Lahoud also "asked the concerned authorities to lodge a letter of complaint with the United Nations Security Council over the new Israeli aggression."

Officials said Foreign Minister Jean Obeid had instructed Lebanon's ambassador to the United Nations, Sami Kronfol, to send such a letter, complaining of the "new aggression."

Beirut also "reserved the right for Lebanon to request a council meeting if and when it sees fit," one official said.