Butte (Montana), Mar. 23 : A light aircraft nose-dived into a cemetery as it approached the Butte Airport in Montana, killing at least seven children and seven adults. US officials have launched probe into the cause of a plane crash.

"We think that it was probably a ski trip for the kids," Federal Aviation Administration spokesman Mike Fergus was quoted by the BBC, as saying.

The pilot had filed a flight plan showing a destination of Bozeman, a ski destination about 85 miles (136km) southeast of Butte. But the pilot cancelled his flight plan at some point and diverted for Butte, Fergus said.

Earlier, 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. We don''t have a lot of information at this time," she said.

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

Tom Hagler, owner of Table Mountain Aviation, described the children as ranging from about 6- to 10 year olds. He let the children into his building to use the restroom.

"There were a lot of kids in the group. A lot of really cute kids," he said.

An eyewitness 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. It smelled like diesel fuel to me. There was nothing left of it... You wouldn''t even know a plane was there," local resident Steve Guidoni.

The local airport has a short runway and is not easy to land there because it is surrounded by mountains. (ANI)