Consular support is being provided to “a number of British nationals and their families” after a tourist yacht sank in the Red Sea off Egypt, the Foreign Office said.
There are reports that four Britons who were on board the vessel south of the coastal town of Marsa Alam are missing.
Amr Hanafy, governor of the Red Sea region, said the yacht was carrying 31 tourists and 14 crew.
Twenty-eight people were saved by rescuers.
A distress call was made from the yacht shortly before dawn on Monday.
The vessel had left Marsa Alam for a five-day sailing.
It was not immediately clear what caused the sinking.
The Egyptian Meteorological Authority warned of high waves on the Red Sea and advised against maritime activity on Sunday and Monday.
The yacht was operated by Dive Pro Liveaboard, which is based in the Egyptian resort of Hurghada.
The company said it has no information on the matter.
Rescue operations are being co-ordinated by the Egyptian military and the Red Sea Governorate.