Almost three dozen divers are missing and feared dead after a 75-foot scuba diving boat caught fire off the coast of California in the early hours of Monday morning.

Ventura County Fire Department said that it had responded to an emergency call at 3:28 a.m. PT Monday to a boat anchored just off Santa Cruz island. They arrived to find the boat engulfed in flames, tweeting a picture of the scene.

The U.S. Coast Guard said that a group of five crew members has been rescued, one with minor injuries with efforts continuing to locate the remaining passengers. Four of the crew members were brought back to shore, while the captain remains at the scene, CNN reported.

The crew was sleeping in the main cabin, while 34 passengers were sleeping below deck when the fire broke out.

The Ventura Country Fire Department initially told local TV station KTLA5 that all 34 of the passengers had died, but a spokesperson for the U.S. Coast Guard would not confirm that.

Capt. Brian McGrath of the Ventura County Fire Department subsequently confirmed in a statement that there were at least some fatalities but would not say how many.

"We're still holding hope that someone may have swam to shore,” Mike Eliason from the Santa Barbara County Fire Department, said. “When they anchor overnight they're pretty close to shore. We have to hope, but we plan for the worst-case scenario.”

The 75-foot boat that caught fire was named Conception and is based in Santa Barbara Harbor. The boat has a maximum capacity of 46 people and operated year-round, according to the website California Diving News. It launched in 1981, the website said.

The Conception set out from Santa Barbara on Saturday and, based on information from MarineTraffic.com, it visited several diving spots around Santa Cruz Island and was due to return to Santa Barbara on Monday evening.

An image of the sleeping quarters of the Conception shows rows of wooden bunks with reading lights and privacy curtains.

This is a developing story