(CNN) -- A three-year-old boy and a police officer were among six people killed in a suicide attack Tuesday morning in northwest Pakistan, police told CNN.

The suicide bomber walked up to a police station in the Bannu district and blew himself up next to a parked police van, said Iftikhar Khan, a local police chief.

Police say 19 people were also injured in the attack.

The Bannu district neighbors Pakistan's tribal region along the Afghan border.

Journalist Nasir Habib contributed to this report.