In U.N. speech, Obama warns Islamic militants to leave battlefield

President Barack Obama used his annual speech to the United Nations on Wednesday to warn Islamic State fighters to "leave the battlefield while they can" and asked the world to back a U.S.-led campaign against the militants in Iraq and Syria.

In a speech to the U.N. General Assembly in New York, Obama said Islamic State must be destroyed, as British Prime Minister David Cameron weighed whether his country would join the military drive that includes U.S. Arab allies.