U.S. won't telegraph when Syria strikes will begin - Rice

WASHINGTON (Reuters) - Ten days after President Barack Obama said he had authorized U.S. air strikes against Islamic State targets in Syria, the White House gave no sign on Friday that attacks were imminent as he prepared to meet world leaders at the United Nations.

At a White House briefing, national security adviser Susan Rice was vague as to when the new air campaign might begin in Syria, and whether Obama would in fact sign off on any final attack plan developed by the Pentagon.