Islamabad, Pakistan (CNN) -- An explosion in northwest Pakistan killed 12 people on Tuesday, police and hospital officials said.
The attacker targeted a police van that was traveling on the outskirts of the town of Dera Ismail Khan in North West Frontier Province. Attackers placed five kilograms (11 lbs) of explosive material on a parked bicycle and detonated it remotely, police said.
Women and children were among the dead, said Nasir Malik Akhtar, a doctor at a local hospital in Dera Ismail Khan, as were three police officers, according to police.
Journalist Nasir Habib contributed to this report.