(CNN) -- A Navy training jet crashed in a north Georgia forest on Monday, killing at least three people aboard and setting more than 10 acres of woodland ablaze, local and federal authorities said.

A fourth person aboard the jet was unaccounted for Monday night, said Harry White, spokesman for the Naval Air Station in Pensacola, Florida. The cause of the crash was under investigation.

FAA spokeswoman Kathleen Bergen said the crash of the twin-engine T-39N trainer caused no injuries on the ground. It went down just north of Morganton, Georgia, about 80 miles north of Atlanta, Fannin County Sheriff's Maj. Keith Bosen said.

"We got reports that it was flying pretty low," Bosen said. The plane had flown north-northeast over the nearby town of Blue Ridge before it went down about 4:40 p.m., he said.

The mountainous area is ringed by national forest land, and the crash set the surrounding woods on fire.

"We have about a 10- to 15-acre fire still working at this time," Bosen said.

The T-39N took off from Pensacola Naval Air Station in Florida, about 400 miles south of Morganton, Bergen said. The jet is a military version of Rockwell's twin-engine Saberliner executive aircraft.



CNN's Nick Valencia, Devon Sayers and Larry Shaughnessy contributed to this report.

