Russia's FSB chief: Russian A321 plane blown up by homemade explosive device; $50 million reward on perpetrators.

Russia's FSB chief: Russian A321 plane blown up by homemade explosive device. (Tass).

Russian A321 plane was blown up by homemade explosive device equivalent up to one kg of TNT, Russian Federal Security Service (FSB) chief Alexander Bortnikov said.

"It can be unambiguously said that this is a terrorist act," Bortnikov said.

According to him, the traces of a foreign-made explosive were found in the airliner debris and the passengers’ belongings.

"In the estimates of our specialists, a self-made explosive device with its power of up to 1 kilogram in TNT equivalent went off aboard the airliner, due to which the plane broke up in the air and this explains the spread of the plane's fuselage parts over a large distance," the Federal Security Service chief said.

The FSB takes measures to find those involved in the terrorist attack on board the Russian airliner in Sinai, the service’s public relations center told TASS.

"FSB and law enforcement agencies of the Russian Federation are taking measures to detect the people involved in the crime," it said.

Russia’s Federal Security Service has declared a $50-mln reward for information about those responsible for the plane crash.

"For providing evidence that will contribute to the detention of criminals a reward of $50 million will be paid," the FSB’s public relations department said. Read the full story here.