General Staff: Russia has lost 340,650 troops in Ukraine.

Ukraine war latest: Russia deploys reserves near Kupiansk, prepares blockade, says commander

Key developments on Dec.

11: * Commander: Russia deploys reserves near Kupiansk, prepares blockade * Russia's FSB claims it detained 18 'Ukrainian agents' in Crimea this year * Air defense downs 18 drones, 8 missiles * UK, Norway announces support coalition to bolster Ukrainian Navy * Sweden...