A couple mourns for victims of a Russian airliner which crashed in Egypt

LONDON — Britain said Thursday there is a significant possibility that the Egyptian affiliate of ISIS was behind a suspected bomb attack on a Russian airliner that killed 224 people in the Sinai Peninsula.

Russia dismissed the claim as speculation and Egypt said there was no indication so far that a bomb caused the crash.

The topic is sensitive for Russia, whose warplanes have launched raids against ISIS in Syria, and for Egypt, which depends heavily on tourism revenues.

Asked if he thought ISIS was responsible, Foreign Secretary Philip Hammond said: “ISIL-Sinai have claimed responsibility for bringing down the Russian aircraft, they did that straight away after the crash.

“We’ve looked at the whole information picture, including that claim, but of course lots of other bits of information as well and concluded that there is a significant possibility.”

British Prime Minister David Cameron said it was more likely than not that a bomb was to blame.

“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.

U.S. and European security sources said evidence now suggests that a bomb planted by the ISIS affiliate in Egypt — Sinai Province — was the likely cause of the crash. The sources stressed they had reached no final conclusions about the crash.

Britain, Ireland and the Netherlands banned flights to and from Sharm al-Sheikh after the crash.