Police official Mohammad Khan says Friday's attack was aimed at the newly appointed district police chief, Zahid Ullah, who escaped unhurt.
Mohammad Khurasani, a spokesman for the Pakistani Taliban, claimed responsibility for the attack and warned of more in the future.
Dera Ismail Khan is a central town in the country's northeast and a gateway to the North and South Waziristan tribal regions, which have were a base for local Taliban until recently when the army in series of operations killed or captured militants.
Violence, however, has persisted in the town.
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