Peshawar: A suicide bomber on Friday targeted a senior Pakistani police commander in the northwestern city of Peshawar, killing at least six people and wounding 11 others, officials said.

A security official said Abdul Majeed Marwat, commander of the paramilitary Frontier Constabulary for Khyber Pakhtunkhwa province, survived the attack and was taken to a military hospital with "only scratches".

"It was a suicide attack, the target was the FC commander," police official Arshad Khan said.

Witnesses said the suicide bomber was on foot and blew himself up when the convoy of the police chief stopped at a military checkpost in the busy cantonment area of Peshawar.

"We have received six dead bodies, including two women. Eleven people were also injured," Sayed Jameel Shah, a spokesman for Peshawar's main Lady Reading Hospital, said.

Shah said the injured included four paramilitary personnel. An AFP reporter saw a pair of legs, presumed to be that of the bomber, at the site.

There was no immediate claim of responsibility but Pakistani police, soldiers and paramilitary units are frequently targeted by domestic Taliban, who have been fighting an insurgency since July 2007.

Violence has been on the rise in the northwest as Pakistan prepares to hold historic elections on May 11. The vote will mark the first democratic transition of power in Pakistan, which has been governed by four military rulers.

There are fears that rampant insecurity could prove a major challenge for the elections, not least in Peshawar, a key electoral battleground and home to 2.5 million on the edge of the tribal belt, a Taliban and Al Qaida stronghold.

The relatively nearby Tirah Valley has offered Pakistan's umbrella Tehreek-e-Taliban a new base in the tribal district of Khyber, beyond the reach of ground troops and posing a heightened threat to Peshawar.

On Tuesday a girls' school teacher was shot dead in Khyber and last Saturday a suicide attack killed 17 soldiers in North Waziristan, the most notorious of the seven districts that make up the semi-autonomous tribal belt.

On March 21, a car bomb killed 15 people at Jalozai, the country's largest refugee camp, as scores of people queued for rations, just outside Peshawar.

Pakistan says more than 35,000 people have been killed as a result of terrorism in the country since the 9/11 attacks on the United States.