One person was killed when a light aircraft crashed into a tree in a village, police said.
Emergency services went to the scene after a member of the public called police reporting that the plane had come down at Aldham near Hadleigh, Suffolk.
After hitting the tree, the plane became submerged in a pond.
It was not immediately clear whether there were any further casualties.
Air accident investigators are on their way to the scene.
An area around the location has been cordoned off, and police, fire and ambulance emergency services remain at the scene.
Details of the aircraft, pilot and any other persons on board are unknown.
An Air Accidents Investigation Branch (AAIB) spokesman said: "The AAIB is aware of the incident and has sent a team to investigate the light aircraft accident near Ipswich."
In a statement on their Facebook page, Suffolk Fire and Rescue Service said crews from Woodbridge, Hadleigh, Needham Market, Bury St Edmunds and Halstead, Essex, are currently in attendance. The water rescue vehicle and water incident rescue crew are also at the scene.