Four bodies have been recovered and four found on the ocean floor after a boat was destroyed by fire off the coast of California, US authorities said. Rescuers were scrambling on Monday to reach more than 30 people who were sleeping below deck on the diving boat <em>Conception </em>when it caught fire. Five members of the crew managed to escaped the blaze, which started in the early hours of Monday. Among the recovered bodies were those of two men and two women, Sheriff Bill Brown said. The cause of the fire is unknown so far. A major rescue operation was under way for the dozens of people trapped on the 22-metre boat, near Santa Cruz Island off the coast from Los Angeles, the coastguard tweeted. Bill Nash, a spokesman for Ventura County, told CNN many people were feared dead. "It's a large boat and we know we have numerous fatalities," Mr Nash said. "I don't have an exact number." But coastguard chief Aaron Bemis said: "The five crew members were able to disembark because they were in the main cabin. "The 34 passengers were below decks. The report we got was they were trapped by the fire." "The fire was so intense that even after it was put out, we're not able to actually embark the vessel and, you know, look for survivors at this point. It's still ongoing."