MINGORA, Pakistan — Pakistani police say three children have been killed in the northwestern Swat Valley while handling an abandoned mortar shell they thought was a toy.

Police official Bakhat Khan said Friday two children were also wounded in Wednesday's incident in the village of Matta.

He says the mortar round might have been lying there since 2009, when the army evicted the Pakistani Taliban from the area. He says security officials have launched a search to clear the region of other unexploded ordinance.

The Swat Valley is the home of Nobel Peace Prize winner Malala Yousafzai, who was shot and wounded in 2012 by militants for promoting girls' education.