Six people were killed when a business jet traveling from Las Vegas to southern California crashed into a field while approaching an airport and then became engulfed in flames, authorities said.

The crash occurred around 4:15 a.m. PT Saturday in Murrieta in Riverside County, according to the National Transportation Safety Board.

The Cessna C550 business jet had departed from Harry Reid International Airport in Las Vegas and "crashed short of French Valley Airport during its second approach," the NTSB said based on preliminary information.

Deputies responding to the crash "located an aircraft fully engulfed in flames in a field," the Riverside County Sheriff's Department said in a statement.

All six occupants aboard the plane were located and pronounced dead at the scene, the sheriff's office said.

The fire from the crash burned approximately one acre of vegetation and was contained by 5:35 a.m. PT, fire officials said.

The NTSB and Federal Aviation Administration are investigating. Investigators with NTSB, which is leading the investigation, are responding to the crash site to document the scene and examine the aircraft.

Radar data, weather information, plane maintenance records and the pilot’s medical records will be requested as part of the investigation, the NTSB said.

A preliminary report is expected to be published in 15 days.

This is the second crash this week near the French Valley Airport. On Tuesday, another small plane crashed shortly after takeoff, killing one and injuring three others, according to the FAA.

ABC News' Amanda Maile, Nicholas Kerr and Amanda Morris contributed to this report.