Russia's transport minister and a team of high-level investigators have begun assisting Egyptian authorities determine what caused a Russian airliner to crash in the Sinai Peninsula, killing all 224 people on board.
As the investigation begins, St Petersburg, the flight's destination, was at the centre of a national day of mourning in Russia. Flags were at half-mast and residents called the crash "terrifying."
The Airbus A321, operated by Russian airline Kogalymavia under the brand name Metrojet, was flying from the Red Sea resort of Sharm el-Sheikh when it went down in central Sinai soon after daybreak on Saturday. It crashed into a mountainous area shortly after losing radar contact near cruising altitude.
On Sunday, a report in the Wall Street Journal said that debris from the tail section was found separate from the rest of the fuselage, which suggests it may have split off midair, people familiar with the investigation told the publication.
So far, at least 163 bodies have been recovered and transported to various hospitals including Zeinhom morgue in Cairo, according to a cabinet statement.
Search efforts resumed at the crash site early on Sunday morning and Russian experts were already at the site helping to recover bodies and begin investigations into the cause. Russian investigators had already visited the morgue, a security source said.
Emergency services and aviation specialists had searched the wreckage on Saturday for any clues to the crash. Both black boxes had been recovered, Egypt's civil aviation minister said.
Judicial and ministry sources told Reuters that Egyptian and Russian investigators would begin examining the contents of the black boxes within hours.
The Russian flag could be seen flying at half-mast over the Russian embassy in Cairo on Sunday morning.