LONDON (AP) – A British air force helicopter crashed near an army base in northern England late Wednesday, killing two military personnel and injuring 10, police said.

North Yorkshire police said some of the injured were in serious condition at nearby hospitals. Earlier, Air Force officials said 12 injured people were taken to hospitals; the discrepancy wasn’t immediately explained.

The Puma helicopter was carrying nine army personnel and three Royal Air Force crew when it came down near Catterick Garrison, a large army base.

The helicopter crashed in a wooded area about 240 miles north of London, Royal Air Force spokesman Michael Mulford said. He said the helicopter was helping the army as part of an exercise at Catterick, the site of the army’s Infantry Training Center.

Air force helicopters were scrambled from nearby bases and arrived at the scene within 10 minutes of the crash just before 9 p.m. local time, he said.

Local resident Andrew Pavey said he saw the helicopter “quite rapidly go straight up into the air and it didn’t sound right.”

“It sounded like the engine was misfiring or something – it was making a hell of a racket,” he told the BBC. “This helicopter went on to its side and then shot off.”

The Ministry of Defense said an investigation into the crash would begin Thursday.

“The board of inquiry will start work … through the night or certainly tomorrow, and they will take as long as it takes to work their way through and determine what happened here,” Mr. Mulford said.