The Iraqi Interior Ministry said Thursday that at least 400 people were killed in a string of suicide bombings targeting an ancient religious sect in northwestern Iraq earlier this week. Ministry spokesman Brig. Gen. Abdul-Karim Khalaf said that 2 tons of explosives were used in the blasts, which crumbled buildings, trapping entire families beneath mud bricks and other wreckage as entire neighborhoods were flattened near the Syrian border. The victims were Yazidis, a small Kurdish-speaking sect that has been targeted by Muslim extremists who consider its members to be blasphemers. Khalaf said 400 people were killed. Local officials earlier had given estimated death tolls ranging from 250 to 500 as bodies were pulled from the rubble and hundreds of wounded were taken to several overwhelmed hospitals across the region.