Two battalions of Russian soldiers crossed the border into Ukraine, the National Security Council in Kyiv said, as government forces and pro-Moscow rebels battled for control of the Donetsk airport.
Russia's War Against Ukraine
Bloomberg Businessweek: Ukraine says Russians cross border as airport battle rages
Unidentified T-72 model tanks stand in pro-Russian rebel-controlled territory near the town of Zugres, east of Donetsk, on Dec. 26, 2014.
