Official negligence contributed to the death toll in Afghanistan’s biggest suicide bombing, which killed 72 people, most of them schoolboys, this month, the interior minister said on Tuesday.

Nine people were killed when a suicide bomber posing as a shepherd attacked police north of Baghdad on Tuesday and at least six civilians died in a spate of shootings by U.S. soldiers, security officials said.

Six people were killed when a suicide bomber attacked provincial police headquarters in Baquba north of Baghdad on Tuesday, police said.