Al Qaeda’s branch in Iraq rallied Muslims to step up the fight while a militant group linked to the terror network promised a “gift” for Eid al-Fitr, a major Muslim holiday starting on Thursday. In an unprecedented move, the Al Qaeda Organization in the Land of Two Rivers posted a statement Wednesday on the Internet confirming the sighting of the new moon to signal the feast. It congratulated Muslims everywhere on the holiday, which marks the end of Ramadan, the month of daytime fasting and prayers. “From Mesopotamia we send our best wishes to the nation of tawhid (monotheism) for...