A helicopter has crashed into the sea in East Yorkshire in England, police have said.
The helicopter was seen crashing off the coast near Flamborough at 1.40pm today, Humberside Police said.
Police, coastguard and ambulance service are at the scene.
A Humberside Police spokesperson said the incident did not involve a police helicopter.
A statement released by police said: "Police received a call from a concerned member of public reporting a helicopter having crashed into the sea off the coast near Flamborough at around 13.40 hours (1.40pm) today.
"Police, coastguard and ambulance service attended the area right away and a search was carried out which resulted in the helicopter being located in the sea off the coast of Flamborough near the lighthouse.
"An area has been cordoned off while the emergency services and coast guard continue their work.
"Initial inquiries are being made in order to try and establish the circumstances which led to the helicopter coming down."
Members of the public have been asked to stay away from the site of the crash due to dangerous cliff edges and aviation fuel in the water.
According to the Bridlington Free Press, a helicopter got into difficulties at around 1.30pm.
Chris Feast, from Flamborough Head Golf Club, said a number of golfers had spotted a helicopter trying to land near the 17th green and then reported hearing a "loud bang and crash".
The Bridlington Lifeboat was launched at 1.59pm.
Eye-witness Chris Palmer said he heard a loud "crack" and the helicopter disappeared out of sight behind the cliffs.
He told BBC Radio 5 Live: "We heard the helicopter. It was like a white, private helicopter going along the coast.
"We all heard this really loud crack and looked up again.
"The helicopter started to descend, almost like a plane when it lands.
"It then went behind the cliff and that's when I called the emergency services.
"I never actually heard it hit the sea."
A Yorkshire Ambulance Service spokeswoman said they received a call at 1.39pm reporting that a helicopter had crashed into a cliff at Flamborough.
She said an air ambulance, an ambulance, rapid response vehicles and the RAF all attended the scene.
The small helicopter was believed to be returning to Humberside Airport when it crashed, a spokesman for the Maritime and Coastguard Agency said.
The spokesman said: "The Humber Maritime Rescue Coordination Centre received a call at 13.40 this afternoon that a small helicopter had gone into the water below the cliff, between the lighthouse and Flamborough Head golf course.
"A coastguard officer was winched down to assess the crash site by the search and rescue helicopter from Leconfield."
A spokeswoman for Yorkshire Air Ambulance confirmed they also had a crew at the scene.
A spokeswoman for the RNLI said two lifeboats had been launched - from Flamborough and Bridlington - and were searching in the area.
She said she had no more details.