PESHAWAR: At least one person was killed and another wounded when a roadside bomb exploded in northwestern Pakistan on Wednesday, police said.

‘The bomb was planted on a roadside in Dera Ismail Khan town and was detonated when a police vehicle approached it,’ local police official Shafiq Khan told AFP.

A passer-by was killed and another person wounded in the attack, he said, adding that a police van was also partially damaged in the explosion.

Dozens of people have died in drive-by shootings and bombings in the Dera Ismail Khan district bordering a restive tribal region in recent months, amid tensions between Sunni and Shia Muslims.

But attacks on police and security forces have previously been blamed on Taliban militants active in the neighbouring South Waziristan tribal district bordering Afghanistan.

Shias account for about 20 per cent of Pakistan's mostly Sunni Muslim population of 160 million and the two groups have usually coexisted peacefully.

More than 4,000 people have died in outbreaks of sectarian violence in Pakistan since the late 1980s.