Kremlin spokesman Dmitry Peskov said "no possible causes should be ruled out" in the investigation of the plane crash in Egypt, that killed 224 passengers, according to Russian news agency TASS.
On Saturday, a Russian airliner crashed into a mountainous area of Egypt's Sinai peninsula after losing radar contact near cruising altitude, killing all aboard. Peskov told journalists that the investigation into the crash has only begun and every possible cause will be examined. Peskov also revealed the main investigation is carried out by Egypt, where the crash occurred.
The Airbus A321, was operated by Russian airline Kogalymavia under the brand name Metrojet. An earlier report stated, Alexander Smirnov, deputy general director of the airline, Kogalymavia said, the crash, in Egypt's Sinai Peninsula could only have been the result of some other "technical or physical action" which caused it to break up in the air and plummet to the ground.
Shortly after the crash, a militant group affiliated to Islamic State in Egypt, Sinai Province, claimed it had brought down the plane "in response to Russian airstrikes that killed hundreds of Muslims on Syrian land", but Russia's Transport Minister told Interfax news agency the claim "can't be considered accurate".
Read: Egyptian experts start examining black boxes, could take days
Also Read: Russian plane crash: First bodies delivered to Russia after plane crashed in Egypt
