Pakistani Taliban have detonated bombs at the campaign offices of two politicians in the country's north-west, police said, killing at least nine people in an escalation of attacks on secular, left-leaning political parties, Belfast Telegraph reported.

In first attack, on the outskirts of Kohat city, a bomb ripped through the office of Syed Noor Akbar, killing six and wounding 10 people, police official Mujtaba Hussain said.

A second bomb targeted a campaign office of another candidate, Nasir Khan Afridi, in the suburbs of Peshawar city. That attack killed three people and wounded 12, police official Saifur Rehman Khan said.

Both politicians, who were not in the offices at the time of the blasts, are running as independent candidates for national assembly seats to represent constituencies in Pakistan's lawless tribal areas, where scores of militant groups operate including some with links to al Qaida. The general elections will be held on May 11.

Pakistani Taliban spokesman Ahsanullah Ahsan claimed responsibility for both attacks, as well as two others against secular political parties in the southern port city of Karachi. "We are against all politicians who are going to become part of any secular, democratic government," he said.