PESHAWAR A roadside bomb blast killed one and wounded at least seven Shia Muslims travelling by mini-bus near a restive town in northwest Pakistan on Thursday, police said.

The explosion occurred near the garrison town of Kohat, which is a key base for Pakistani troops battling Al-Qaeda and Taliban militants in the semi-autonomous tribal districts on the border with war-torn Afghanistan.

'Seven people were injured in the bomb blast,' local police official Shafiq Khan told AFP.

'It appears to be a sectarian attack as all the passengers in the van were Shias,' he said. The blast was caused by a crude, makeshift device, he said.

Shias account for around 20 per cent of Pakistan's mostly Sunni Muslim population of 160 million.

Although the two groups usually coexist peacefully, more than 4,000 people have died in outbreaks of sectarian violence since the late 1980s.

Northwest Pakistan is beset with militant violence led by Taliban fighters who fled over the border following the US-led invasion of Afghanistan.

Extremist attacks blamed on Taliban and Al-Qaeda-linked militants have killed more than 1,800 people across Pakistan since July 2007.