The suicide bomber, who was about 14-years-old, was wearing a school uniform, a senior Pakistani military official said. 

The military official asked not to be named because he was not authorized to talk to the media. 

The teenager detonated his explosives after walking onto the grounds where army recruits were receiving their morning training. 

The bomber was either carrying the explosives in a bag or wearing a suicide vest, officials said. 

A school for children of military recruits is located inside the training facility. The attacker was probably pretending to be a student there. 

The attack took place in Mardan, a district 50 kilometers (31 miles) north of Peshawar in Pakistan's Khyber-Pakhtunkhwa province, formerly known as the North West Frontier Province.