Hanalei Bay is closed to swimming after a shark was spotted in the water Tuesday afternoon, Kauai Fire Department said.

Lifeguards reported seeing a six-foot gray shark swimming near a surf spot known was “Grandpa’s” fronting the Anae Road beach parking lot.

Warning signs have been posted along the beach and the public is advised to stay out of the water until further notice.

The beach will be closed until at least tomorrow morning when lifeguards will reassess, the fire department said.