British Prime Minister David Cameron said it was more likely than not that a bomb brought down a Russian airplane over Egypt last week.
"We cannot be certain that the Russian airliner was brought down by a terrorist bomb, but it looks increasingly likely that that was the case," Cameron said on Thursday before a meeting with Egyptian President Abdel Fattah El-Sisi who is on a visit to Britain.
He said Britain had acted before the investigation was complete because the intelligence they had "gave us the concern that it was more likely than not it was a terrorist bomb".
"We need to put in place more security at that airport so it's safe to fly people home. That's our priority, that's what we'll work with the Egyptians to do," he said.
He also said that "more security was needed at Sharm El-Sheikh airport".