An aircraft and helicopter collided in mid-air Friday, northwest of London and a "number of casualties" were reported, authorities said.
Fire and ambulance services rushed to the scene at 12:06 pm GMT (7:06 am EST) near Aylesbury in Buckinghamshire. Two ambulance crews, two ambulance officers and a rapid response vehicle were deployed, the South Central Ambulance Service said.
The Air Accidents Investigation Branch said it was sending a team to the site of the accident, which is in dense woodland.
The crash took place near Waddesdon Manor, which is managed by the Rothschild Foundation, a family charitable trust, on behalf of the National Trust. The manor said the crash did not happen at the site and there were no casualties at the manor.
A nearby military base, RAF Halton, also said no military aircraft were involved.
Buckinghamshire Fire and Rescue Service, in a tweet, said firefighters are assisting other emergency services at the scene of the accident.
The Air Accidents Investigation Branch has also sent its team to investigate the collision.
(With inputs from AP.)
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