The bulk of the Ukrainian army is concentrated in eastern Ukraine, where it has been locked up in fighting with Moscow-backed separatists in a nearly eight-year conflict.
Putin's declaration paves the way for Russia to openly send troops and weapons to the long-running conflict pitting Ukrainian forces against Moscow-backed rebels.
“The likelihood of more substantive escalation on the Ukrainian boarders as for today is viewed as low,” according to the Ukrainian Ministry of Defense.
If Russia invades, some of Kharkiv’s 1 million plus people say they stand ready to abandon their civilian lives and wage a guerrilla campaign against one of the world’s greatest military powers.