Two Lebanese military officials confirmed to the Associated Press that a vessel landed in Batroun, about 30 kilometres north of Beirut, and abducted a Lebanese citizen.
Neither gave the man's identity or said whether he was thought to have links to Lebanon's Hezbollah group.
They did not confirm whether the armed men were Israeli.
Speaking to Lebanon's Al-Jadeed TV, Minister of Public Works and Transport Ali Hamie declined to go into details or answer questions about whether it was thought to be an Israeli operation.
A Lebanese man captured by armed men was reportedly a civilian ship captain. (AP PHOTO)
Three Lebanese judicial officials told AP the incident occurred at dawn on Friday, adding that the captain might have links with Hezbollah.
The officials said an investigation is looking into if the man is linked to Hezbollah or working for an Israeli spy agency and Israeli forces came to rescue him.
Both the military and judicial officials spoke on the condition of anonymity as they were unauthorised to share details about the incident or the ongoing investigation.
Hezbollah issued a statement calling what happened a "Zionist aggression in the Batroun area."
The statement did not give details or confirm whether one of Hezbollah's members was captured by Israel.
Israel's military said it was looking into local media reports that said its forces captured a senior member of Hezbollah's naval force during the operation.
Israel has carried out in the past commando operations deep inside Lebanon to kidnap or kill Hezbollah and Palestinian officials.
Residents of the apartment building where the man was seized said the armed group introduced themselves as state security.
"We were terrified. They were breaking into the apartment next to ours," Hussein Delbani told The Associated Press near where the man was captured.
"I thought a state agency was doing a security operation," said Delbani, who was displaced from south Lebanon a month ago when the Israel-Hezbollah war erupted.
He said he saw from his balcony people down on the coast and they screamed again for him to go inside.
Hamie told Al-Jadeed the man was a captain of civilian ships.
He graduated in 2022 and in late September joined the Batroun's Maritime Sciences and Technology Institute for additional courses.
Hamie said that the man lived some 300 metres from the institute.
Hamie's remarks came shortly after two Lebanese journalists posted a video on social media showing what appeared to be about 20 armed men taking away a man from in front a house, his face covered with his shirt.
Kandice Ardiel, a spokesperson for the UN peacekeeping force deployed in south Lebanon, denied allegations by some local journalists who said that the peacekeepers helped the landing force in the operation.
The UN mission, known as UNIFIL, has a maritime force that monitors the coast.
"Disinformation and false rumours are irresponsible and put peacekeepers at risk," Ardiel said.
