Russian President Vladimir Putin has bitterly condemned the downing of a Russian jet on the Turkey-Syria border.
He described it as a "stab in the back" committed by "accomplices of terrorists".
Turkey says its jets shot at the plane after warning that it was violating Turkish airspace. But Moscow says it never strayed from Syrian airspace.
Nato held an extraordinary meeting at member Turkey's request to discuss the incident.
Its Secretary-General, Jens Stoltenberg, has said allied assessment of the incident shows that the Russia warplane did fly into Turkish airspace.
One of the two crew members who ejected from the downed plane was killed by fire from the ground, the Russian military said. The fate of the other is unclear.
A Russian soldier was killed when the helicopter he was on came under fire during a search and rescue mission, a spokesman added.