Moscow: Russia pounded Islamic State targets in Syria after confirming that a bomb attack brought down its passenger jet over Egypt last month, killing all 224 people on board.
President Vladimir Putin pledged to hunt down and "punish" those behind the attack, without blaming any specific group, as he ordered an intensification of Moscow's campaign in Syria and vowed "vengeance".
Russia's security agency announced a USD 50-million (47 million-euro) reward for information leading to the capture of those behind the attack on the Airbus jet, which crashed in the Sinai peninsula shortly after leaving Sharm el-Sheikh resort on October 31.
Cairo said it was enhancing security in airports around the country over the possibility the plane was "targeted by a terrorist attack", although the Egyptian probe into the disaster has yet to reach a conclusion.
"It is not the first time that Russia confronts barbaric terrorist crimes", Russian President Vladimir Putin said in a meeting with his security chiefs.
"The murder of our people in Sinai is among the bloodiest crimes in terms of victims," he said in comments released yesterday, vowing to hunt down those responsible.
"We will search for them anywhere they might hide. We will find them in any part of the world and punish them," he said.
Islamic State jihadists have said they attacked the plane -- the deadliest assault on a Russian target since the Beslan school massacre by Islamist rebels from the North Caucasus in 2004 -- just days ahead of a wave of killings in Paris also claimed by the group that left at least 129 dead.
Putin and French leader Francois Hollande agreed in a phone call to "ensure closer contact and coordination" in their operations in Syria, the Kremlin said, as the Russian strongman ordered his navy to work with French forces in the Mediterranean "as allies".
Both countries have been targeting IS fighters, although the US-led coalition France is part of has sparred with Russia over its backing of forces loyal to Syrian President Bashar Al-Assad.
Russia's security chief Alexander Bortnikov told Putin that traces of explosives of "foreign production" had been found on the plane wreckage and that the jet carrying tourists back from Egypt was brought down by a home-made bomb with a force equivalent to one kilo of TNT.
"We can say unequivocally that this was a terrorist attack," Federal Security Service (FSB) head Bortnikov said.