Obama warns Putin of further costs over Ukraine - White House

WASHINGTON (Reuters) - U.S. President Barack Obama warned Russian President Vladimir Putin in a call on Monday that Moscow would face further costs if its actions in Ukraine persisted, the White House said in a statement. "The president expressed grave concern about Russian government support for the actions of armed, pro-Russian separatists who threaten to undermine and destabilize the government of Ukraine," the statement said. "The president noted Russia's growing political and economic isolation as a result of its actions in Ukraine and made clear that the costs Russia already has incurred will increase if those actions persist," it said. (Reporting by Jeff Mason; Editing by Sandra Maler)