PESHAWAR, Pakistan: The death toll from a suicide blast at a security checkpoint in northwest Pakistan has risen to 33, after more bodies were found and several people died in hospital, police said Sunday.

The attack happened Saturday near Peshawar, the capital of North West Frontier Province, as lawmakers in the national parliament and four provincial assemblies were electing Asif Ali Zardari as Pakistan's new president.

"The death toll has risen to 33, as 11 wounded died in hospital overnight and rescue teams recovered six bodies from the debris," provincial police spokesman Riaz Ahmed told AFP by telephone.

Five of those killed were policemen, he said. About 80 others were wounded and receiving treatment in hospital.

"The blast was very powerful," Ahmed said, adding that the vehicle used in the attack was loaded with about 40 kilogrammes of explosives.

The force of the blast destroyed some 60 shops and two houses in the area, he said.

A security official said the attack could be part of a backlash against the Pakistani military's intensified campaign to root out Taliban-linked militants hiding in the lawless rugged tribal areas bordering Afghanistan.

Former president Pervez Musharraf had been a key ally of the United States in its efforts to combat militancy in the border area, which Washington says is being used as a launch pad for rebel attacks on US-led forces in Afghanistan.

But Pakistan's fragile coalition government has been struggling to tackle the violence that has seen nearly 1,200 people killed in bombings and suicide attacks across the country in the past year.

Musharraf resigned last month, paving the way for Zardari, the widower of slain former premier Benazir Bhutto, to rise to power.

- AFP/yb