Military investigators from Russia stand near the debris of a Russian airliner at the site of its crash at the Hassana area in Arish city, north Egypt, in this Nov 1, 2015 file photo. [Photo/Agencies]

MOSCOW - The Kremlin said for the first time on Tuesday that a bomb did bring down a Russian passenger plane that crashed over the Sinai Peninsula in Egypt on Oct 31, killing all 224 people on board.

"One can unequivocally say that it was a terrorist act," Alexander Bortnikov, the head of Russia's FSB security service, told a meeting chaired by President Vladimir Putin, according to a transcript published on the Kremlin's web site.