Security tape is strung inside the Holy Cross Cemetery in Butte, Mont., where a small, single-engine plane crashed in just south of the local airport on Sunday. (Walter Hinick/Associated Press)

A small plane crashed Sunday as it approached an airport in Montana, killing at least 14 people, including several children, a U.S. federal official said.

The single-engine, turboprop plane crashed about 166 metres from the airport in Butte while attempting to land, U.S. Federal Aviation Administration spokesman Mike Fergus said. The Montana Standard reported online that the plane crashed in Butte's Holy Cross Cemetery.

An investigator with the National Transportation Safety Board offered few details at a news conference in Butte on Sunday night. No cause of the crash was given.

"We are just beginning our investigation," Kristi Dunks said. "We don't have a lot of information at this time.

"Certain family members were contacted," she said. "At this point, I don't have an exact number."

The aircraft had departed from Oroville, Calif., and the pilot had filed a flight plan showing a destination of Bozeman, Mont., about 136 kilometres southeast of Butte. But the pilot cancelled his flight plan at some point and headed for Butte, Fergus said.

Preliminary reports indicate the dead include numerous children, he said. There were no known fatalities on the ground, he added.

"We think that it was probably a ski trip for the kids," Fergus said.

The plane was registered to Eagle Cap Leasing Inc. in Enterprise, Ore., Fergus said. He didn't know who was operating the plane.

Calls to local authorities were not immediately returned.

Plane nosedives into cemetery

Witnesses told the Standard that they saw the plane crash nose first into the cemetery.

Martha and Steve Guidoni, who were at a gas station across from the cemetery, said the plane "just nose-dived into the ground."

"My husband went over there to see if he could do anything," Martha Guidoni said.

Butte Silver-Bow Sheriff John Walsh said there were a few people at the cemetery at the time of the crash, but no one on the ground was injured.

Fergus said the Pilatus PC-12 aircraft was manufactured in 2001.

National Transportation Safety Board spokesman Keith Holloway said investigators were expected to arrive in Butte late Sunday or early Monday.

The crash is the fourth major plane accident in the U.S. in three months.

Last December, Continental Airlines plane veered off a runway and slid into a snowy field at Denver International Airport, injuring 37 people. No one was killed.

All 155 people on board survived after a U.S. Airways jetliner landed in New York's Hudson River in January when a flock of geese disabled both engines, and a commuter plane fell on a house in a suburb of Buffalo, N.Y., killing all 49 passengers and a man in the home in February.