A 39-year-old surfer has died after a shark attack off California coast at Surf Beach in Santa Barbara County, BBC News reported.

Sheriff's officials named the victim as Francisco Javier Solorio Jr.

The sheriff's department said the attack was witnessed by a friend of the victim, who swam to his aid and pulled him out of the water. The friend started first aid while another surfer called for help, but the victim was pronounced dead by paramedics at the scene.

The officials said the victim died after being bitten in the upper torso. Police added that the type of shark involved in the attack and other details were still under investigation.

Surf Beach is located on Vandenberg Air Force Base, but remains accessible to the public. "We've had shark sightings up and down the Santa Barbara coastline pretty frequently recently," Lt Erik Raney told AP.

Last month, warning signs were posted at Santa Barbara Harbor, about 105km (65 miles) south-east of Surf Beach, after a large great white shark was spotted by a surfer.

Lt Raney said Surf Beach had not displayed any public alert notices so far.

But officials at Vandenberg advised people to stay away from the beach following Tuesday morning's attack.

On Oct 22, 2010, surfer Lucas Ransom was attacked by a great white shark at the same beach and died from loss of blood.

A friend of the 19-year-old Santa Barbara college student who witnessed that attack said the shark was 18-20ft long.

Nevertheless fatal shark attacks remain rare. In 2011, the International Shark Attack File recorded 75 unprovoked attacks worldwide. Twelve people died as a direct result of their injuries.