Russia is observing a national day of mourning Sunday for the 224 people killed in a plane crash Saturday in Egypt's Sinai Peninsula.
Nearly all of the passengers aboard the Metrojet charter flight were Russian tourists returning to St. Petersburg from the Egyptian resort town of Sharm el-Sheikh. Three Ukrainians are also among the dead.
Emergency crews have recovered at least 129 bodies and both of the plane's black boxes, which record flight data and pilot communications.
Egyptian President Abdel Fattah al-Sisi on Sunday said the investigation into the crash "could take months."
Militants claiming affiliation to the Islamic State said they shot down the Airbus A-321. But aviation and military experts believe the group does not have missiles that could have reached the plane's altitude of 9,100 meters.
The aircraft went down roughly 100 kilometers south of the town of El-Arish, about 20 minutes after taking off from Sharm el-Sheikh before dawn Saturday.
Egyptian Civil Aviation chief Hossam Kamal said safety checks before the flight did not turn up any problems and said the pilot did not issue an SOS before the plane disappeared.
Two major European airlines - Air France and Lufthansa - said they would stop flying over the area for safety reasons.