A shark attacked a Minnesota man off the north shore of the Hawaiian island of Kauai on Thursday, prompting lifeguards to close the area for a day.

The man, whose name is logged as "confidential" in an incident list provided by the Hawaii Department of Land and Natural Resources, was attacked in clear water about 120 yards from shore in Hanalei Bay by a 5-foot-long reef shark.

Lifeguards did not see the attack, the Kauai County Fire Department said. The man suffered cuts to his hands, noted by lifeguards, and opted to drive himself to medical treatment, according to the Fire Department.

Lifeguards posted "No Swimming" and "Shark Sighted" signs along the beach at Hanalei Bay and told people to stay out of the water.

Those signs were removed Friday morning, but lifeguards continued to discourage swimming on unmonitored beaches because of dangerous water conditions, according to a statement from the county.

Earlier this month, another Minnesota man encountered a tiger shark while paddleboarding off the coast of Maui. He was not hurt, but his surfboard was mangled.

Ben Farniok is a University of Minnesota student on assignment for the Star Tribune. The Associated Press contributed to this report.