(Agencies)
Updated: 2007-10-01 16:02

PESHAWAR, Pakistan - A burqa-clad suicide bomber set off a blast that killed at least 15 people Monday at a crowded police checkpoint in northwestern Pakistan, police said.

Pakistani police officers examine the site of a suicide bombing in Bannu, about 180 kilometers (110 miles) south of Peshawar, Pakistan on Monday, October 1, 2007. A suicide bomber set off a blast that killed at least 15 people and injured 22 others at a crowded police checkpoint in northwestern Pakistan, police said. [AP]

The bomb, which injured 22 others, apparently was in a rickshaw that was being examined at a police checkpoint around 8:25 am local time in the town of Bannu, said police officer Habib Khan.

He said it was unclear if the blast was detonated by the driver or the passenger wearing the burqa, an all-encompassing outer garment worn by women. It wasn't immediately confirmed that the bomber was a female, but police said early evidence collected at the scene suggested it was.

"We have confirmed that the passenger sitting in the rickshaw was wearing a burqa and detonated the bomb, but we are checking whether the suicide bomber in a burqa was a man or a woman," said Interior Minister spokesman Javed Iqbal Cheema.

While there have been reports of some women being trained to carry out suicide bombings in Pakistan, it was not immediately clear if any have ever undertaken such an attack.

Bannu police chief Ameer Haamza Mahsud said the casualty figures were high because scores of people were milling about at a nearby bus stand.

The blast killed four police officers and 11 other people, including the bomber, army spokesman Maj. Gen Waheed Arshad said. Because the attack occurred in a public place, he said he did not believe it was aimed at security forces.

The district hospital in Bannu reported that at least seven of the injured were in critical condition.

Bannu is near the North Waziristan tribal region, about 110 miles south of Peshawar.

In recent months, militants have staged almost daily attacks on security forces in North Waziristan since scrapping a peace agreement with the government.

Militants accused authorities of violating the September 2006 deal by redeploying troops to checkpoints vacated under terms of the accord. Officials said the troops returned because of deteriorating security. Most of the combat has taken place in the rugged mountains along the Afghan border where the US fears al-Qaida is regrouping and that Osama bin Laden is hiding.

Pakistan is a key ally of the US in its war on terror and says it has about 90,000 troops in the northwest tribal areas to combat militancy and prevent infiltration into neighboring Afghanistan.