HADERA, Israel — Israeli police on Tuesday were scouring the waters off the country’s Mediterranean coast for a swimmer who they fear may have been attacked by a shark, in an area that for decades has seen close encounters between marine predators and beachgoers who sometimes seek them out.

A day later, the beach near Hadera was closed off as search teams searched the sea by boat and underwater equipment for the swimmer. The man’s identity is unknown, but Israeli media said he had gone to swim with the sharks.

A swimmer is missing following an extremely rare shark attack off the coast of northern Israel on Monday. It happened in the sea at Hadera, about 40km (25 miles) north of Tel Aviv. The incident was witnessed by people on Olga Beach, who can be heard yelling in shock in footage posted on social media.