City lifeguards yesterday posted signs advising beachgoers to stay out of the water after a 10-foot shark was spotted about 2:15 p.m. in waters off Mä'ili Beach Park.

Bryan Cheplic, spokesman for the city Emergency Services Department, said a diver spotted the shark about 500 yards offshore and swam in to report it to lifeguards.

Lifeguards immediately checked the area, confirmed the sighting and determined that the shark was displaying aggressive behavior, Cheplic said.

Beachgoers were asked to stay out of the water for one mile on either side of Mä'ili Beach Park.