London - Four people have died after a helicopter crashed in thick fog in the eastern England county of Norfolk on Thursday, according to local police.
Police were called to the accident scene near the town of Beccles at 19:30 local time (19:30 GMT) after members of the public reported hearing a loud crash, according to Norfolk Constabulary.
Officers were deployed to the scene and searched the area with help from a police helicopter and the crash site was located.
"The crash site is in a field containing some wooded area and all four occupants on board the helicopter were pronounced dead at the scene," it said in a statement.
The scene had been sealed off as police investigators carried out initial enquiries. A team from the Air Investigation Branch was expected to arrive later.
"Emergency services are working together in difficult conditions to secure the scene and carry out an initial investigation into the circumstances," said Inspector Louis Provart.
"Our thoughts are with the family and loved ones of those who have sadly lost their lives this evening," Provart added.
The identity of the occupants will be released after their next of kin have been informed.
Police confirmed the helicopter was a civilian aircraft, with early reports suggesting it was bound for Northern Ireland.
Three ambulances, two doctors and one rapid response car attended the scene.
Local resident Roland Bronk said it was "very foggy" in the area while another wrote on his Twitter page that he couldn't "see my hand in front of my face" due to the weather.
A Met Office forecaster confirmed "there has certainly been some fog around south Norfolk".
The crash site is 72km from where a US military helicopter came down during a training exercise in January, killing four crew.