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.
Some aviation experts raised the possibility that a bomb on board the Airbus brought it down, while others cited an incident in 2001 when the aircraft grazed the runway with its tail while landing.
Metrojet firmly denied that the crash could have been caused by either equipment failure or crew error.
A U.S. infrared satellite detected a heat flash over the Sinai Peninsula at the time the plane went down, but the data is still being analyzed to determine the cause of the flash, CBS News reports.
Egyptian President Abdel-Fattah el-Sissi said Tuesday that the security situation in the Sinai Peninsula is under "full control" and that claims by the Islamic State group that it downed the plane were "propaganda" aimed at damaging the country's image.
In an interview with the BBC released Tuesday, el-Sissi also reiterated his assertion that the cause of the crash may not be known for months and that until then, the causes should not be speculated on.
Islamic State militants said on the day of the crash that they had "brought down" the Russian plane to avenge those killed as a result of Moscow's recent air campaign in Syria, launched in support of ISIS adversary President Bashar Assad.
But the group did not provide any evidence to back up its claim, and militants in northern Sinai have not to date shot down commercial airliners or fighter jets.
The Associated Press contributed to this report.