Two Britons were among the 83 people killed when a series of suspected car bombs ripped through the Egyptian holiday resort of Sharm El-Sheikh.
Around 200 people were wounded by the blasts that hit a bazaar and tourist hotels in the Red Sea resort.
Two other Britons, a 14-year-old girl and a 30-year-old man, are in a critical condition in hospital, a spokeswoman for the British embassy said.
An Egyptian security official said the dead included British, Russian, Dutch, Kuwaitis, Saudis and Qataris.
Earlier, the UK ambassador, Sir Derek Plumbly, said: "We believe that there are eight British people who have been injured. Three are still in hospital here, two have been evacuated to Cairo by air ambulance during the course of the night."
An emergency phone line, 020 7008 0000, has been set up by the Foreign Office for concerned relatives.
The group, calling itself the Abdullah Azzam Brigades in Syria and Egypt, said that its "holy warriors targeted the Ghazala Gardens hotel and the Old Market in Sharm El Sheikh".
Shaken European tourists spoke of mass panic and hysteria as people fled the carnage, with bodies strewn across the roads, people screaming and sirens wailing.
The regional governor said two car bombs and possibly a suitcase bomb had rocked the resort that is popular with divers.
One blast tore the front off the Ghazala Gardens Hotel in Naama Bay, the site of most of the resort's luxury hotels, where people were feared trapped in the rubble.
A car broke into the hotel compound and exploded in front of the building, South Sinai Governor Mustafa Afifi said. Egyptian tourist hotels always have police guards at the gates.
"I have never been so scared in the whole of my life," British tourist Samantha Hardcastle said of the bombs. "The explosion we felt was very violent and the hotel we are staying in shook. It was absolutely horrific."
The first explosion hit the old market in Sharm El-Sheikh town, filling the air with fire and smoke, residents said.
"I saw a car flying up in the air, people running," restaurant owner Yehya Mohammed said by telephone. "I do not think I will ever forget this in my life. This is a horrible setback for tourism here."
Sharm residents said they heard two more explosions coming from Naama Bay in quick succession, blasts that could be felt six miles away.
Witnesses said the first of these hit the hotel and the second a taxi rank. The blasts came at a time when many tourists were still out in bars and markets in the popular and hitherto safe resort.
itv.com