See What Brought Down Russian Jet: Russian Officials Say "Homemade, Heavy, Bomb Brought Down The Jet"

The bomb that Russian officials said had been planted in a Russian jet by terrorists was extremely heavy, according to a new analysis.

Russian officials said an analysis of the plane and customer baggage revealed evidence of the explosive device. The plane crashed over Egypt’s Sinai Peninsula on Oct. 31 with 224 passengers on board.

Alexander Bortnikov, the head of the Russian Federal Security Service, called the bomb "a homemade explosive device with an equivalent of 1 kilogram of TNT."

The explosion led to the plane "'breaking up' in midair," Bortnikov said, "which would explain the scattering of the plane’s fuselage [main body] across a wide area." 

Russian investigators showed the findings to Russian President Vladimir Putin, who vowed to track down those responsible.

"We will not wipe tears from our heart and soul. This will remain with us forever," Putin said today. "But this will not prevent us from finding and punishing the criminals. We must do that without an expiration date, we must know them by name. We will find them everywhere, where they have hidden themselves. We will find them at any point on the planet and we will take retribution."

ISIS claimed responsibility soon after the crash.

Putin said Russia's military and aerial work in Syria "should be strengthened so that the criminals understand that retribution is unavoidable."

Russia is offering a $50 million reward for information on those responsible.

In response to Russia's findings, Secretary of State John Kerry said, "We concur there was an explosion that brought it down, but we’re not privy to their investigative information."

"We have some instinct about what might have happened" but the info is "not conclusive," Kerry added.

Egyptian officials said they will take Russia's findings "into consideration."

"Egypt stresses its cooperation with its Russian counterparts in curbing terrorism," Egyptian officials said, adding that the country has tightened security measures in airports