CAIRO (Reuters) - Ansar Bayt al-Maqdis, Egypt's most active militant group, has sworn allegiance to Islamic State, a statement from Ansar said Monday night. Ansar had previously told Reuters that it sought inspiration and advice from Islamic State, the radical al-Qaeda offshoot that has taken over swathes of Iraq and Syria, drawing U.S.-led airstrikes as it tries to remake the map of the Middle East. "After entrusting God we decided to swear allegiance to the emir of the faithful Abu Bakr al-Baghdadi, caliph of the Muslims in Syria and Iraq and in other countries," the statement said. ...