A powerful roadside bomb went off near a police vehicle in southwestern Pakistan on Wednesday, killing an officer and wounding five others, police said.

No one immediately claimed responsibility for the attack in the town of Qilla Abdullah in Baluchistan province. The town is located 75 kilometres (30 miles) north of Quetta, the provincial capital.

Police officer Abdullah Achakzai said the victims were taken to a nearby hospital.

The attack came as Prime Minister Imran Khan was in Baluchistan on a day-long visit. The premier was far from where the attack happened.

Baluchistan has been the scene of a low-level insurgency by small separatists groups demanding more autonomy and a greater share in the region's natural resources, such as gas and oil.

Terrorists from the Pakistani Taliban and the Islamic State group are also active in the province.