An Afghan official says at least three civilians were killed when their vehicle was blown up by a roadside bomb in the northern part of the country.

Abdul Wasi Basil, spokesman for the governor of Kunduz province, says the target of the attack Saturday was a district police chief, who was wounded in the blast.

The explosion, in Imam Sahib district, killed the police chief's brother and driver, and wounded his son.

No one immediately claimed responsibility for the attack. Roadside bombs have been a weapon of choice for Taliban insurgents for many years, and are often used to target officials and members of the security forces.

Police bear the brunt of the attacks because they don't have the protection of bases and are less-equipped than the army.