Ukraine rebels free Swedish hostage; Obama seeks unity against Russia

Pro-Russian activists block the entrance to a television station in Donetsk, eastern Ukraine April 27, 2014. REUTERS/Baz Ratner

KUALA LUMPUR/SLAVIANSK, Ukraine (Reuters) - Pro-Russian rebels paraded European monitors they are holding in eastern Ukraine on Sunday, freeing one but saying they had no plans to release another seven as the United States and Europe prepared new sanctions against Moscow.

U.S. President Barack Obama called for the United States and Europe to join forces to impose stronger measures to restrain Moscow. In a move senior U.S. officials said may come as early as Monday, the White House said it would add names of people close to President Vladimir Putin and firms they control to a list of Russians hit by sanctions over Ukraine, and also impose new restrictions on high-tech exports.