Many civilians were killed when a truck bomb detonated near the front checkpoint gate of the U.S. Consulate in Herat early Friday, the American envoy to the country said. Civilians and contractors who worked at the consulate were among the victims, U.S. Ambassador James Blair Cunningham said. No Americans died in the attack, officials said.The Taliban claimed responsibility for the attack, in which the attackers possibly fired rocket-propelled grenades and assault rifles at Afghan protective forces at the gates of the consulate, State Dept, spokeswoman Marie Harf said. Shortly thereafter, the entire truck exploded, she said. One civilian and two Afghan National Police were killed in the attack, Herat Police Chief General Rahmatullah Safi said.