A Spanish tourist has died following a suspected carbon monoxide leak in a London hotel.
Another Spanish man, who is believed to have been staying in the same room, remains in hospital in a critical condition.
Some 29 people were evacuated from the Mayflower Hotel, in Kensington, which remains closed, after emergency services were called just before 1.50pm on Monday.
Firefighters wearing breathing apparatus carried out a sweep of the hotel to check for elevated carbon monoxide readings, the London Fire Brigade (LFB) said.
Scotland Yard said initial tests found the readings were high.
A man was pronounced dead at the scene, while another man, who is in his 30s, was taken to hospital.
A spokesman from Spain's Ministry of Foreign Affairs said:
"The local authorities from the London police have confirmed at least two Spanish citizens in the hotel have been effected.
"One of those has died, unfortunately, and the other one has been transferred to hospital.
"Our consulate in London is in contact with the local authorities and the families are receiving consular help."
The Metropolitan Police said a post-mortem examination is yet to be held and the death is being treated as "unexplained".
Officers are conducting a joint investigation with the Royal Borough of Kensington and Chelsea's environmental health department.
"Initial tests indicated a high reading of carbon monoxide, though the investigation has not yet concluded," a Met spokesman said.
"The hotel was evacuated and remains closed while the investigation continues. The scene has now been made safe."
LFB said it sent three fire engines and two fire rescue units to the hotel after reports of a possible carbon monoxide leak.
A spokesman added:
"Crews wearing breathing apparatus isolated the gas supply, ventilated the building and carried out a sweep of the property to check for elevated readings. "Approximately 29 people were evacuated to another hotel."
The hotel could not be reached for comment.