Metrojet Flight 9268 crashed in Egypt’s Sinai Peninsula after breaking apart in midair, killing all 224 people on board. It was en route to St. Petersburg from the Red Sea resort of Sharm el-Sheikh. The plane crashed about 185 miles north, near a town called Housna, according to Egyptian authorities. European investigators who analyzed the two flight recorders from the Metrojet plane are saying the crash was not an accident.

The investigators said the cockpit voice recorder shows an explosion and the flight data recorder confirms the explosion is not accidental because there is no sign of mechanical malfunction during the initial part of the flight. Everything is fine during the first 24 minutes, then in a fraction of a second there is a blackout and no more cockpit conversation, convincing investigators there was a bomb on board.

CNN Aviation Analyst Richard Quest said there would have been different data on the black boxes if there was a catastrophic failure than if there was an explosion. The key is what happened just before the data suddenly stops, he said.

President Putin has accepted the recommendations of the National Anti-Terrorist Committee to suspend flights with Egypt. He has also instructed to provide assistance to Russian citizens to return from Egypt. In addition, the President has instructed to engage with the Egyptian side to ensure the safety of air traffic,” the Kremlin said.

Days after authorities dismissed claims that ISIS brought down a Russian passenger jet, a U.S. intelligence analysis now suggests that the terror group or its affiliates planted a bomb on the plane. The officials stressed that no formal conclusion has been reached by the U.S. intelligence community and that U.S. officials haven’t seen forensic evidence from the crash investigation.

Intelligence also suggests someone at the Sharm el-Sheikh airport helped get a bomb onto the plane, one U.S. official said. The signs pointing to ISIS are partially based on monitoring of internal messages of the terrorist group which are separate from public ISIS claims of responsibility.

Egyptian authorities, who are leading the investigation into the crash, haven’t publicly responded to reports on U.S. intelligence. Since the crash, they’ve downplayed the possibility that terrorism could be involved.