A man has been arrested after four people died when the car they were travelling in plunged into a reservoir, police said.
A fifth person, the female driver of the car, survived the tragic accident which happened at the Bwlch y Gle Dam, Clywedog, Llanidloes, mid Wales.
The woman, a holidaymaker who has not be named, is receiving medical attention. She was at the wheel of a Peugeot 807.
A Dyfed Powys police spokesman said: "A local man was arrested at the scene on suspicion of causing death by dangerous driving and is in custody at present."
Police said the body of one man had been recovered from the car, which remained submerged in water.
The second car involved in the accident, which happened on the B4518 road, was a Ford Mondeo.
"We can also confirm that the woman holidaymaker driving the Peugeot managed to escape from the car and is now receiving medical attention - but tragically four other occupants of that car have been killed," the police spokesman said.
"The body of a man has been recovered from the car - but the other bodies remain submerged and arrangements are being made to recover them."
He said the road had been closed and would remain so for some time.
He added: "We are in the process of informing next of kin, and no further information in relation to the victims will be released until this process has been completed."