Russia's security chief has said a "terror act" brought down the Russian A321 airliner in Egypt last month, killing all 224 people on board, BBC reported on Tuesday.
"Traces of foreign explosives" were found on debris from the Airbus plane, FSB chief Alexander Bortnikov told Russian President Vladimir Putin.
Putin vowed to "find and punish" those responsible for the attack over the Sinai peninsula, the report said.
An Islamic State affiliate has claimed the attack. Nearly all the dead were Russians.