The crash happened close to the town of Butte's airport
US officials have launched an inquiry into the cause of a plane crash in the state of Montana that killed 14 people, including seven children.
The light aircraft nosedived into a cemetery near the town of Butte on Sunday. There were no survivors.
The pilot was flying from Oroville, California, when he diverted to Butte, officials said. He tried to land but crashed 500ft (150m) from the airport.
The children were probably going on a ski trip, officials said.
One witness said the aircraft was making so many turns before the crash that he thought it might be a stunt plane.
"All of a sudden it went into a nosedive," he told US television network CBS.
"I noticed the pilot trying to pull up but he was extremely low to the ground and he didn't pull up in time."
Karen Byrd of the Federal Aviation Administration (FAA) said seven adults and seven children had been killed.
The Pilatus PC-12 is a Swiss-made turboprop plane
That revised downwards an earlier reported death toll of at least 16.
At a news conference in Butte late on Sunday, National Transportation Safety Board investigator Kristi Dunks gave few details.
"We are just beginning our investigation," she said.
"We don't have a lot of information at this time."
FAA officials said earlier that the plane - a Pilatus PC-12 Swiss-made turboprop aircraft - had crashed at about 1530 local time (2130 GMT) on Sunday in cloudy weather conditions.
There was speculation that the plane, which media reports say is designed to carry a maximum of 11 or 12 passengers, might have been overloaded.
The local airport has a short runway and it is not easy to land there because it is surrounded by mountains, John Emeigh, a reporter for The Montana Standard newspaper, told the BBC.
Reports suggest the pilot had filed a flight plan showing a destination of Bozeman, a ski destination about 85 miles (136km) south-east of Butte.
But the pilot cancelled his flight plan at some point and diverted to Butte, Federal Aviation Administration (FAA) spokesman Mike Fergus said.
Local resident Steve Guidoni said he saw the plane nosedive into the ground as he was driving by the cemetery.
"It just went straight into the ground. I went over there to try to help. I thought maybe I would pull someone out of the fire," Mr Guidoni was quoted as saying by the Associated Press news agency.
"It smelled like diesel fuel to me. There was nothing left of it... You wouldn't even know a plane was there," he said.