The U.S. Embassy in Egypt instructed its staffers Tuesday not to travel anywhere in the Sinai Peninsula following Saturday's crash of a Russian airliner that killed all 224 people on board. In a statement, the Embassy said the travel ban was in place as a precautionary measure pending the outcome of the investigation into the crash. The Metrojet Airbus A321-200 was en route from Sharm el-Sheikh to St. Petersburg when it went down over the northern Sinai Peninsula approximately 23 minutes after takeoff. The overwhelming majority of the passengers were Russian holidaymakers flying home. Meanwhile, Russian officials said the first 10 bodies of victims were identified by their families Tuesday, Russian officials said. Alexei Smirnov of the Russian emergency situations ministry said that a total of 140 bodies and more than 100 body parts were delivered to St. Petersburg on two government planes on Monday and Tuesday and that a third plane is expected to bring more remains later on Tuesday. Confusing reports and theories emerged on Monday as to what could have caused the crash.