Militant group Ansaru says more than 2,800 foreign workers are dead . U.S. officials say Ansaru is an offshoot of the Islamist militant group Boko Haram , which Nigerian authorities say is behind a recent rash of killings and kidnappings in the country . Boko Haram is believed to be an offshoot of Boko Haram , U.S. officials say . The victims are from U.S. , Greece , Lebanon and U.S. . The foreigners worked for a construction firm in northern Lebanon .
Militant group Ansaru says more than 2,800 foreign workers are dead . Boko Haram is believed to be an offshoot of Boko Haram , U.S. officials say . The victims are from U.S. , Greece , Lebanon and U.S. . The foreigners worked for a construction firm in northern Lebanon .