Ukraine's acting President Alexandr Turchynov said Saturday he has placed the country's armed forces on full combat alert, warning that any military intervention in the country would lead to war.
Speaking live on Ukrainian TV, Turchynov said he has also ordered intensified security at nuclear power plants, airports and other strategic infrastructure, Xinhua reported.
Russia has no justification for any "act of aggression," Turchynov said in a late night announcement made hours after Russia's parliament gave President Vladimir Putin a green light to use military force to protect Russian interests in Ukraine.
"All explanations about dangers to Russian citizens or Russian- speaking Ukrainians have been devised," he said.
Meanwhile, Ukraine's Prime Minister Arseny Yatsenyuk said he had urged Russia to return its troops to base in the southern Crimea region during a phone call with Rusian Prime Minister Dmitry Medvedev and called for talks.
"Military intervention would be the beginning of war and the end of any relations between Ukraine and Russia," Yatsenyuk said.