Obama, allies say Russia's Ukraine threat to peace, security

WASHINGTON (Reuters) - President Barack Obama and the leaders of Britain, Germany and Poland expressed "grave concern" on Sunday over Russia's intrusion into Ukraine, which they called a breach of international law and a threat to international peace and security. Obama spoke to each leader in a separate phone call, the White House said. "The leaders stressed that dialogue between Ukraine and Russia should start immediately, with international facilitation as appropriate," the White House said in a statement. (Reporting by Mark Felsenthal; Editing by Peter Cooney)