Kiev, Ukraine (CBS) - Ukraine put its armed forces on full combat alert on Saturday and warned Russia that any military intervention in the country would lead to war.
After a more than three-hour meeting with security and defense chiefs, Acting President Oleksandr Turchynov said there was no justification for what he called Russian aggression against his country.
Standing beside Turchynov, Prime Minister Arseny Yatsenyuk said he had urged Russia to return its troops to base in the Crimea region during a phone call with 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 told reporters.
CBS News national security correspondent David Martin reported earlier Saturday that Russia flew hundreds of troops into Crimea Friday and that between 2,000 and 6,000 Russian troops were already based in Crimea, according to U.S. officials. Those troops were deployed from their bases to secure other facilities in Crimea.
Martin also reports that Ukraine's armed forces have told the American ambassador to Kiev that they do not intend to resist the Russian troop movements.
The U.S. is not making any military movements in response to Russia's actions, Martin reports.