There was no immediate comment from Israeli and Lebanese authorities.
Pro-Hezbollah journalist Hassan Illaik said in a post on X that a large group of Israeli troops made a landing in the resort town and captured the man, before departing on speed boats.
He shared CCTV footage appearing to show soldiers walking in a street, two of them holding a person.
Lebanese transport minister Ali Hamiye, who represents Hezbollah in Lebanon's government, said the video was accurate but did not provide further details.