LOS ANGELES - A US man was killed early on Friday in a shark attack on a California beach, officials said.

'One person has been confirmed dead following a shark attack while boogie boarding at Surf Beach,' said authorities at Vandenberg Air Force Base, 215km north-west of Los Angeles.

The man in his early 20s was in the water with a friend at the time of the attack, officials said without revealing further details of the attack or what kind of shark was involved.

'Our first responders were on scene to assist in rescue efforts,' said Richard Boltz, 30th Space Wing commander at the base. The beach was closed for at least 72 hours.

According to local press reports the shark was between four and six metres long.

The last death of this kind involved a great white shark in California in 2008, when a 66-year-old man was attacked as he swam with friends off a beach in San Diego.

US man killed in shark attack