Obama warns Russia over Ukraine

US President Barack Obama has warned Russia there will be "costs" for any military intervention in Ukraine. He said he was deeply concerned by reports of Russian military movements inside the country. Ukraine's acting president has accused Russia of deploying troops to Crimea and trying to provoke Kiev into "armed conflict". Russia's UN ambassador said any troop movements in Crimea were within an existing arrangement with Ukraine. Speaking from the White House, President Obama commended Ukraine's interim government for its "restraint", according to BBC.