The Russian ambassador has thanked the Duke of Cambridge and his colleagues for their efforts in rescuing the crew of a stricken cargo vessel.
Two men were airlifted to safety by an RAF helicopter co-piloted by William as the MV Swanland sank in the Irish Sea after being hit by an "enormous wave" in the early hours of Sunday morning.
Another person was later recovered from the sea but pronounced dead while an air-sea search for five missing seamen is continuing.
All eight members of the crew were Russian citizens.
In a letter to the Duke, posted on his embassy's website, Russian ambassador Alexander Yakovenko said: "All day long we were anxiously following the rescue operation searching for Russian seamen from the sunk Swanland vessel.
"We know that you took an active part in the rescue and the two seamen were saved thanks to your selfless effort under the bad weather conditions. Let me express to you and your colleagues my deepest gratitude for saving the lives of the Russian citizens."
The Swanland sank about 10 miles west of the Lleyn peninsula in North Wales.
William's search and rescue team, based at RAF Valley on Anglesey, was called into action when the cargo ship issued a mayday call at around 2am when its hull cracked. The Duke is understood to have been involved in the operation for several hours.
The two surviving members of the crew of the Cook Islands-registered vessel were pulled from the water, clinging to life rafts, soon after the alarm was raised. Both men were taken to hospital in nearby Bangor as a precaution and later discharged.
The search for their five missing colleagues resumed at around 8am, the Maritime and Coastguard Agency (MCA) said