U.S. officials investigating Saturday's deadly crash of a Russian passenger jet in Egypt are looking at whether the plane was taken down by a bomb planted by the Islamic State terrorist group or one of its affiliates, NBC News and CNN reported Wednesday, each citing an unidentified U.S. official.The investigation is ongoing, but evidence suggests a bomb caused the plane carrying 224 passengers and crew to break apart mid-air above the Sinai Penninsula, according to NBC News. There were no survivors.The reports came hours after the British government announced that it is suspending all flights from the Egyptian resort city where the plane took off, calling the move a "precautionary measure" in light of information suggesting the jet "may well have been brought down by an explosive device."The Airbus plane bound for St. Petersburg broke up mid-air and crashed in the Sinai Peninsula just 23 minutes after taking off from the resort community of Sharm el-Sheikh International in Egypt, according to the Associated Press . Airline officials said Monday that they believe an "external impact" caused the crash."We rule out a technical fault of the plane or a pilot error," said Alexander Smirnov, deputy general director of the Metrojet airline. "The only possible explanation could be an external impact on the airplane."In televised remarks, Alexander Fridlyand, an expert from an aviation research center in Moscow, suggested that "a quick plunge from high altitude may indicate that a plane was hit by a bomb explosion in its luggage compartment," the AP reported An Egyptian group associated with ISIS has claimed responsibility for the tragedy but has offered no evidence. Russian Minister of Transportation Maxim Sokolov initially said that rumors that Airbus A321 was shot down by Islamic State terrorists are "inaccurate."Several major airlines announced plans to reroute flights to avoid flying over Egypt's Sinai Province.The flight was carrying 217 passengers, including 17 children, plus seven crew members, according to the BBC . Most of the passengers were believed to be tourists. Of them, 214 were Russian and three were Ukrainian.