Investigators of the Russian plane crash in Egypt are "90 percent sure" the noise heard in the final second of a cockpit recording was an explosion caused by a bomb, a member of the investigation team told Reuters on Sunday. "The indications and analysis so far of the sound on the black box indicate it was a bomb," said the Egyptian investigation team member, who asked not to be named due to sensitivities. "We are 90 percent sure it was a bomb." Asked to explain the missing 10 percent, the investigator said: "I can't discuss this now."

ISIS militants fighting security forces in Egypt's Sinai Peninsula have said they brought down the Airbus A321, which crashed 23 minutes after taking off from the resort of Sharm al-Sheikh a week ago en route to St Petersburg, killing all 224 passengers. Egyptian officials say they are examining all possible scenarios on what could have caused the disaster but have cautioned against jumping to conclusions.

A noise was heard in the last second of the cockpit voice recording from the Russian plane that crashed last week in Egypt's Sinai Peninsula, the head of the joint investigation team said Saturday. The statement bolstered U.S. and British suspicions that the plane was brought down by a bomb. However, Ayman el-Muqadem warned it was too early to say what caused the plane to apparently break up in mid-flight. Analysis of the noise was underway. "All scenarios are being considered ... it could be lithium batteries in the luggage of one of the passengers, it could be an explosion in the fuel tank, it could be fatigue in the body of the aircraft, it could be the explosion of something," said El-Muqadem, who is Egyptian and leading the investigation committee that includes experts from Russia, France, Germany and Ireland, where the plane was registered. El-Muqadem appeared alone at the news conference in Cairo. U.S. and British officials have cited intelligence reports as indicating that the Oct. 31 flight from the Sinai resort town of Sharm el-Sheikh to St. Petersburg was brought down by a bomb on board. All 224 people onboard, most of them Russian tourists, were killed. El-Muqadem said debris was found scattered across a 13-kilometer (8-mile) stretch of desert, indicating the Airbus A321-200 broke up mid-air, but initial observations don't shed light on what caused it. Some pieces of wreckage were still missing, while the recovered pieces will be taken to Cairo for analysis, he said.

Egyptian airport and security officials told The Associated Press on Saturday that authorities were questioning airport staff and ground crew who worked on the plane and had placed some employees under surveillance. The officials all spoke on condition of anonymity because they were not authorized to speak to the media. Also Saturday, Egypt's foreign minister complained that Western governments had not sufficiently helped Egypt in its war on terrorism. Egypt's past calls for assistance and coordination on terrorism issues from "the countries that are now facing the danger" had not been dealt with seriously, Sameh Shoukry told a news conference. "European countries did not give us the cooperation we are hoping for," he said. Shoukry also said countries that have suspended flights to Sharm el-Sheikh which include the U.K. and Russia, though the foreign minister did not specifically name them did not share the intelligence that drove their decisions with Cairo. Egypt "expected that the information available would be communicated to us instead of being broadcast" in the media, he said.

Russia announced Friday it was suspending flights to all of Egypt, joining the UK and Ireland, which had stopped flights to Sharm el-Sheikh. At least a half-dozen Western European governments told their citizens not to travel there. Empty charter planes have been flying to Sharm el-Sheikh to bring home stranded Russian and British tourists. Passengers were banned from checking in luggage reflecting an apparent concern about security and luggage-screening procedures at the airport. Russia has returned 11,000 of its tourists from Egypt in the last two days. Thousands of mostly Russian and British tourists are stranded at Sharm al-Sheikh airport, where the Airbus A321 took off for St Petersburg before crashing 23 minutes into the flight. Around 80,000 Russians were left in Egypt after the Kremlin grounded all flights to the country on Friday following the crash, due to security concerns. A British official said on Saturday it could take 10 days for all British tourists to be flown home. Maya Lomidze, acting director of the Russian Association of Tour Operators, said authorities were sending 93 empty planes to Egypt on Saturday and Sunday to bring tourists home. The Russian Emergencies Ministry also said it would send planes to transport the checked baggage of Russian tourists who were forced to leave their suitcases behind. Thousands of tourists waited in slow-moving security lines at the Sharm el-Sheikh airport on Saturday as they tried to board charter flights home. Many complained about a lack of information from travel agents and airlines, but seemed to accept tight security measures. Designer Georgy Kononov and his family hoped to catch a flight to Moscow after a seven-hour delay. He said he agreed with Russia's decision to suspend flights to Egypt. "When we're talking about the safety and security of people, it's more important than the business," he said, though he added that there should have been better planning for such a complicated situation.