(CNN) -- An American cruise ship passenger was reported overboard Wednesday, and the U.S. Coast Guard joined the search in the Pacific Ocean northeast of Hawaii.
The 54-year-old woman was witnessed intentionally going overboard from the Grand Princess, Princess Cruises said, adding that the witness' account was confirmed by closed-circuit television.
The Grand Princess was on day three of a 15-day cruise round-trip sail from San Francisco to Hawaii.
The crew notified the service that the woman had gone overboard about 750 miles northeast of Hilo, the 14th Coast Guard District in Honolulu said. The Coast Guard listed her age as 30.
The passenger was last seen about 1 p.m., the cruise line said. It said it immediately contacted the FBI and the Coast Guard. It gave the distance from Hilo as approximately 650 miles.
The ship changed course to search, and an HC-130 Hercules airplane crew was en route from Air Station Barbers Point in Hawaii, the Coast Guard said. Its statement provided no details on what may have occurred.
CNN's Drew Iden contributed to this report.