US: More than 100 civilians killed in Iraq bombing in March

WASHINGTON — A Pentagon investigation has found that more than 100 civilians were killed after the U.S. dropped a bomb on a building in Mosul, Iraq, in March.

The probe found that the U.S. bomb triggered secondary explosions from devices clandestinely planted there by Islamic State fighters. And the military says the secondary blasts caused the concrete building to collapse.

It was likely the largest single incident of civilian deaths since the U.S. air campaign against IS began in 2014.

The lead investigator is Air Force Brig. Gen. Matthew Isler. Isler says 101 civilians in the building were killed, and another four died in a nearby building. He says 36 civilians remain unaccounted for.

The deaths represent about a quarter of all civilian deaths since the U.S. air campaign began.