The United States Navy has named two of its submarine servicemen who died after falling overboard in UK waters.
The nuclear-powered submarine is based at Norfolk, Virginia
They were among four crewmen who were working in poor weather on the outside casing of the USS Minneapolis-St Paul in Plymouth Sound, Devon, on Friday.
The men were taken to hospital, where two of them were pronounced dead.
The dead men were named as Senior Chief Thomas Higgins, 45, of Paducah, Kentucky, and Petty Officer 2nd Class Michael Holtz, 30, of Lakewood, Ohio.
The US Navy said in a statement on Sunday that the cause of the accident remained under investigation.
A joint inquiry is being carried out by Devon and Cornwall Police, the United States Navy and the Ministry of Defence (MoD).
The nuclear-powered submarine was leaving Plymouth's Devonport naval base at the time of the incident after a week's stay.
Coastguards said the four sailors were tied to the 110m (362ft) vessel and were being "battered about" by the weather.
The men were taken to Derriford Hospital in Plymouth, where Senior Chief Higgins and Petty Officer Holtz were pronounced dead.
The two other men were treated for minor injuries and transferred to the sick bay at the HMS Drake to recover.
The submarine pilot, the two rescued sailors and MoD personnel who were escorting the vessel out of the port were being questioned by police in the inquiry.
They may also speak to personnel aboard the submarine.
A US Navy spokesman said: "Our thoughts and sympathies are first and foremost with the families and loved ones of the sailors who sadly lost their lives in this incident."
The Virginia-based submarine has been operating under the US Sixth Fleet since October.
It has a complement of 137 officers and enlisted crew and can reach speeds exceeding 25 knots (29mph). Its weapons include torpedoes and Tomahawk cruise missiles.