One man has died after a boat sank in the English Channel off the Sussex coast, police said.
A major search including lifeboats and helicopters was launched on Sunday morning after the vessel went down off Shoreham shortly before 6am.
Sussex Police said that the boat was believed to have come out from Brighton Marina with four people on board.
One man was rescued alive and two others are thought to be missing.
A Sussex Police spokesman said it was assisting the coastguard "after a man was pulled alive from the sea by fishermen just after dawn on Sunday".
He added: "It is believed that he was with three other men on a boat out of Brighton Marina.
"The body of one man has been recovered from the sea and brought ashore by Coastguard helicopter.
"A search of sea and coastline is under way to find any survivors."
Lifeboats from Brighton and Shoreham and two coastguard helicopters are being assisted by other local boats in the search for the missing men.
The rescued man was found in the water by a fishing vessel two miles from Shoreham harbour at around 5.50am, the UK Coastguard said.
The survivor is a 45-year-old man from London who was discovered "clinging to a buoy" west of Shoreham, police said.
The force spokesman said: "It is thought that the boat may have left Brighton Marina around midnight and the incident may have happened a couple of hours later, but the facts are not clear at this time."
The body of the dead man was found at around 8.15am.
An investigation involving the Marine Accident Investigation Branch has been launched.