Image caption Pakistan has seen a spike in bomb attacks in the run-up to polls

At least eight people have been killed and more than 40 injured in a suicide bomb attack in the Pakistani city of Peshawar, officials say.

The blast took place on a busy road and hit a passenger bus, media reports say.

The bomber detonated the explosives after passing a police vehicle.

Such attacks have soared in Pakistan ahead of elections on 11 May, with dozens killed in attacks targeting politicians and political parties.

On Sunday, bomb attacks by the Taliban on the campaign offices of election candidates left at least eight people dead and 23 injured.

The Taliban have vowed to continue a campaign of attacks against political parties they see as secular.

Reports say that a bomb has also exploded near the home of an ANP candidate in the city of Mardan, damaging the wall of his compound.

No group has said it carried out this latest attack in Peshawar.

Television footage showed the damaged bus and motorcycle wreckage. The wounded were taken to hospitals in the city.

Correspondents say violence has marred the campaign for Pakistan's landmark election, in which one civilian government is due to be succeeded by another for the first time in the country's history.