The Kremlin has announced that traces of explosives were found in the debris of the Russian passenger jet that crashed in Egypt last month.

According to the Russian Federal Security Service, Metrojet Flight 9268 was brought down by a bomb estimated to contain 2.2 pounds of explosives.

Russia initially played down assertions from Western countries that the October 31 crash, which killed all 224 people on board, was the work of terrorists, saying it was important to wait for the outcome of the official investigation.

But today, Alexander Bortnikov, the FSB chief, said “You can definitely say that this is a terrorist act.”

According to a statement from the Kremlin, Putin said,

Our air operation in Syria will not just continue — it must be strengthened so the criminals understand retribution is imminent.

Russia didn’t waste any time acting on Putin’s payback vow: the Kremlin launched a massive overnight bombardment across Syria, including airstrikes on the ISIS stronghold of Raqqa, according to U.S. and Russian officials.

The FSB, which is the successor to the KGB, also announced that it is offering a $50 million reward for information on who brought the plane down.

Putin vowed to hunt down the perpetrators:

We have to do it without any period of limitation; we need to know all their names. We will search wherever they may be hiding. We will find them anywhere on the planet and punish them.

Anyone who tries to help the criminals should know that the consequences for trying to shelter them will lie completely on their shoulders.

*Article by Lily Dane