People stand next to flowers at a makeshift memorial for the victims of the Russian MetroJet Airbus A321 crash. | Getty / People stand next to flowers at a makeshift memorial for the victims of the Russian MetroJet Airbus A321 crash on November 4, 2015 in Saint Petersburg. Russian jet was downed by bomb, U.S. and U.K. officials say "While the investigation is still ongoing we cannot say categorically why the Russian jet crashed,'' the British prime minister's office said.

The Russian plane crash that killed 224 people was likely caused by a bomb on board, according to the British government and news reports.

"While the investigation is still ongoing we cannot say categorically why the Russian jet crashed,'' the British prime minister's office said in a statement. "But as more information has come to light we have become concerned that the plane may well have been brought down by an explosive device.''


"There is a definite feeling it was an explosive device planted in the luggage or somewhere on the plane," a U.S. official told CNN. The officials believe the conventional explosive may have been planted by Islamic State or an affiliate, CNN said.

The U.K. and Ireland have suspended all flights from Sharm el-Sheikh in Egypt, according to the Associated Press.

British Ambassador to the U.S. Peter Westmacott said that the investigations were ongoing but there was reason to believe it was a possibility so they made the announcement.

“We don’t take these decisions lightly, as you know," he said on CNN Wednesday afternoon. “The government has a duty of care to British subjects.”

White House Press Secretary Josh Earnest said similar restrictions on U.S. carriers are unnecessary because none regularly operate out of the peninsula and it isn't the last point of departure for any aircraft that operates regularly in the U.S.

Earnest noted that the FAA has had a notice in place prior to the weekend’s incident advising U.S. civil aviation to avoid operations over the Sinai Peninsula under 26,000 feet because of hazards associated with extremists.

“If it were the last point of departure for any aircraft operating in the United States there would be a whole set of security regulations imposed to insure the safety of the traveling public,” Earnest said.

Ranking Member of the House Permanent Select Committee on Intelligence Rep. Adam Schiff (D-Calif.) said he'd been briefed on the crash and urged people "not to jump to any conclusions yet."

"We are still trying to confirm what the cause of the crash was. It is certainly possible that it was an explosive, but it’s also possible that this was a structural problem with the plane, with the tail section of the plane. " Schiff said in an interview on CNN. "So at this point, I don’t think we’re prepared to draw any conclusions. But obviously we’re investigating it, and directing our intelligence resources to try to determine the cause of the crash."

The terrorist group known as Islamic State or ISIS claimed responsibility for the crash; U.S. officials initially cast doubt on that claim.

