A suicide bomber of some 15 years of age, blew himself up in a crowded mini van in northwestern Pakistan on Tuesday, killing himself and 18 other people, news reports said.
The boy detonated an explosive vest when security forces stopped the vehicle in the town of Dera Ismail Khan and asked him to turn himself over.
Two police officers, two soldiers and passengers died in the blast, Pakistan's Aaj and other news channels reported. The town's police chief said the boy was 14 or 15 years of age.
Around a dozen people were injured in the explosion. Body parts were littered around the scene of the blast, confusing initial casualty estimates.
In a separate incident some 50 km to the west, two paramilitary soldiers and two civilians were killed in a clash involving pro-Taliban militants in the South Waziristan tribal district that borders Afghanistan.
The Frontier Corps troops were killed when gunmen fired several rockets in a night-time raid on a checkpoint, news reports said.
Security forces retaliated by firing rockets which hit a house, killing two people and injuring four.
The border area has seen a surge in violence since the military stormed Islamabad's radical Red Mosque in July.