"A naval commando force kidnapped a civilian," the military source said on condition of anonymity, adding an investigation was underway to determine whether the operation was carried out by Israel.

A Lebanese judicial official said Israel was likely behind the "kidnapping operation", the first of its kind since the Israel-Hezbollah war erupted in September.

Speaking on the condition of anonymity to discuss sensitive matters, the official said there was a "90 percent chance" that Israel was responsible.

Contacted by AFP, the Israeli military said they were checking reports of the incident.

Lebanon's official National News agency said an "unidentified military force" carried out a "sea landing" on the shore of Batroun, south of Tripoli, at dawn on Friday.

The force "went with all its weapons and equipment to a chalet near the beach, kidnapping a Lebanese man... and sailing away into the open sea on a speedboat," the NNA said.

An acquaintance of the abductee identified him as a student at the Maritime Sciences and Technology Institute (MARSATI) in Batroun.

He was taken from student housing near the Batroun institute, but was a resident of the Shiite-majority town of Qmatiyeh further south, said the acquaintance who spoke on the condition of anonymity for security concerns.

He was completing courses to become a sea captain, the source told AFP, adding that the man was in his 30s and was well known by the teaching staff at the centre.

The Christian-majority city of Batroun has been relatively sheltered from the Israel-Hezbollah war that has pummelled south Lebanon, the southern suburbs of Beirut and the eastern Bekaa Valley.

The war since September 23 has killed more than 1,900 people in Lebanon, according to an AFP tally of health ministry figures though the real number is likely higher due to data gaps.