HONOLULU -- Authorities have called off their search for a swimmer who went missing on Oahu's North Shore after firefighters failed to spot him.

The Fire Department earlier Thursday had resumed looking for the man after a tattered pair of black shorts belonging to him was found at Papailoa Beach. Searchers were conducting shoreline patrols and aerial surveillance to look for signs of the missing man.

The victim, a visitor, had reportedly rented a surfboard in Haleiwa and was surfing for the first time when he disappeared in windy and rough conditions with 4-foot waves. The swimmer was identified as a 35-year-old from Beijing who has been living in Sunnyvale, Calif.

The search began Tuesday when a female companion reported him missing. The next day, three large tiger sharks were seen near a body floating off Papailoa Beach. Helicopter crews had spotted a figure and sharks about 300 to 400 yards off the shore of Laniakea Beach Park. The tiger sharks spotted from the air appeared to be about 12- to 15-feet long.

"Shortly before dark (on Tuesday), we had a sighting of a body in the surf zone. The Coast Guard helicopter thought they saw a body, a couple hundred yards offshore," Capt. Terry Seelig said.

The presence of the sharks prevented divers from entering the water to retrieve the body. Officers were also trying to assess shark activity in the area to assist the Ocean Safety Division in determining the status of a shark alert. Lifeguards had posted signs warning people to stay out of the water for one mile in each direction of the sighting. The signs were removed Thursday morning after Ocean Safety and Lifeguard Services personnel re-assessed the situation and determined there were no sharks in the immediate area.

The man's family was being assisted by the Visitor Aloha Society of Hawaii.