Russia plans to intensify air strikes on Islamic State (IS) in Syria after its investigators concluded that the Metrojet plane travelling from Egypt crashed due to a bomb blast.
The Airbus plane carrying Russians from Egypt's tourist destination Sinai, crashed last month killing 224 people onboard.
IS has claimed that it bombed the plane in retaliation to Russia's attacks on Syria.
Russia has been denying the US and Europe's claims that the crash was a terrorist act.
However, Russian security service FSB head Alexander Bortnikov informed a meeting headed by President Vladimir Putin on Monday that an improvised explosive device with 1.5kg of TNT exploded in the plane mid-air.
Traces of TNT were found in the debris.
Following the revelations, Putin has ordered the air force to intensify air strikes on the militant outfit in Syria.
"It (the air campaign) must be intensified in such a way that the criminals understand that retribution is inevitable.
"The tears in our soul and heart will remain with us forever, but this won't stop us from finding and punishing those guilty," Putin was quoted by Reuters as saying.
Separately, France targeted IS bases in northern Syria on Tuesday with fresh air strikes.
Reuters reported that French warplanes attacked a command centre and a jihadist recruitment centre in Raqqa. Ten fighter jets were launched from the UAE and Jordan.
France intensified its air strikes on the Middle Eastern country after a series of terror attacks in Paris on Friday that killed at least 129 people.