At least 10 people were killed and eight injured Tuesday morning in an explosion in northwestern Pakistan when a passenger van detonated an improvised explosive device planted along a road in the tribal area bordering Afghanistan, a Pakistan government official said.

Tariq Hassan, a top official in the Kurram tribal area, said the van was heading to Sadah from Godar when it ran over the bomb.

Those killed included five children and a woman, while the injured were rushed to Parachinar District Hospital.

In Rawalpindi, a Defense Ministry spokesman said that an army helicopter had been sent to Parachinar to airlift the seriously wounded to Lady Reading Hospital in Peshawar, the capital of Khyber Pakhtoonkhwa province.

The Kurram tribal area borders Ningarhar province in eastern Afghanistan, where on April 13 the United States dropped the largest nonnuclear bomb ever used in battle on what it claimed was a network of caves and tunnels used by Islamic State fighters.