Amid possibly loose talk by Vladimir Putin of using nuclear weapons in the Ukraine imbroglio, Kiev is shifting its focus from defeating pro-Russia separatists in the eastern part of the country to fending off a deeper cross-border incursion by Russia. The Ukrainian army will stop trying to eject the separatists amd move to a defensive strategy against "a full-scale invasion" by Russian troops, said Ukraine's Defense Minister Valeriy Heletey. The BBC quoted the minister as saying Moscow is launching "a great war" in Ukraine. Kiev's drastic change in tactics was announced as the latest round of talks among Ukraine, Russia and the rebels ended in Belarus with no agreements. Russia, which insists it has no troops in Ukraine, said Monday that it is ruling out military intervention and wants a political solution.