An Afghan official says three children were killed and four wounded after they found an unexploded mortar in a field while playing.

Fazal Mohammad Ishaqzia, the governor of Panjwayi district in the southern Kandahar province, said the children killed Wednesday all belonged to the same family. Kandahar Gov. Samim Khopalwaq said they were all younger than 12.

Afghanistan has been at war for more than three decades and munitions left over from various conflicts regularly cause casualties.

In a separate incident, Interior Ministry spokesman Sediq Sediqqi says an army officer was arrested Tuesday with 19 kilograms (41 pounds) of heroin in an army vehicle in the northern Baghlan province.

Brig. Gen. Abdul Samad Habib, who commanded a recruitment center in Balkh province, has been charged with drug smuggling,