Moscow says two Russians were killed after one of its warplanes was shot down by Turkey along the Syrian border.
One of the pilots on the plane is dead, with the other missing, according to Russia - and a marine involved in a rescue attempt was also killed.
Military alliance NATO has promised to stand by member Turkey but is calling for calm and diplomacy.
It comes as French President Francois Hollande continues his push for more action against the Islamic State in Syria and Iraq in the wake of the Paris attacks.
Hannah Lucinda-Smith of the Times newspaper is at the Turkey-Syria border - she says people there believe the Russian plane did encroach on Turkish airspace.
IN: "It does…
OUT: …it down."
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