CAIRO, Egypt - The new leader of al-Qaida in Iraq killed two U.S. soldiers whom the group abducted last week, an insurgent umbrella group said in a Web statement posted Tuesday. The statement, which could not be authenticated, said the two soldiers were "slaughtered," suggesting they had been beheaded by Abu Hamza al-Muhajer. The Arabic word used in the statement, "nahr," is used for the slaughtering of sheep by cutting the throat and has been used in past statements to refer to beheadings. The claim of responsibility was posted on an Islamic militant Web site where insurgent groups regularly post...