The Russian Federal Security Service director offered a reward of $50 million for information on those behind the attack on the A321, RT reported.
Earlier on Tuesday, the Kremlin said for the first time that a bomb had ripped apart a Russian passenger jet over Egypt last month and promised to hunt down those responsible and intensify its air strikes on Daesh in Syria in response.
Egypt has opened an investigation into the causes of the crash, and allowed Russia to take part in the probe. No official and final report by Egypt has been issued yet.
The incident killed all 224 passengers on board.
Editor's note: This article has been edited from the source material
