Fighting in Syria between moderate rebels, al Qaeda intensifies - U.S

NEW YORK (Reuters) - Moderate Syrian rebels are engaged in their fiercest fighting to date with al Qaeda-affiliated fighters on Syria's northern and eastern borders, a senior U.S. State Department official said on Tuesday.

"There is a real firefight," the official said of battles between al Qaeda's Islamic State of Iraq and the Levant (ISIL) and the Free Syrian Army led by Salim Idriss, a more moderate group of rebels trying to oust Syrian President Bashar al-Assad.