Russian security chief said an act of terror brought down the Russian A320 airliner in Egypt last month killing all 224 people on board.
“Traces of foreign explosives” were found on debris from the Airbus plane, FSB chief Alexander Bortnikov told Russian President Vladimir Putin.
Russian president vowed to “find and punish” those behind the attack over the Sinai Peninsula.
A branch of so-called Islamic State said it downed the plane.
In a statement on the Kremlin’s website, Bortnikov said a bomb had been planted on board the Kogalymavia jet, equivalent to up to 1kg of TNT.
It blew up on 31 October, shattering the plane mid-air, he said, “which explains the wide dispersal of fuselage pieces”.
