A suicide bomber on a motorbike rammed into a minibus carrying security personnel, detonating a blast Monday that killed at least six people in the Pakistani garrison city of Rawalpindi, police said.
The bus was destroyed and several other people were wounded in the explosion on a road running through a bazaar near the offices of the army's National Logistics Cell, said Bisharat Abbasi, the local police chief.
Army spokesmen were not immediately available for comments, and it wasn't clear which branch of the armed forces the passengers were from.
Police and soldiers cordoned off the area, and erected a screen around the site. The blast was so powerful that it blew the roof off the bus, and damaged several nearby vehicles.
Shaukat Khan, owner of a nearby tire-repair shop, said he was sweeping the sidewalk when the explosion happened.
"It was very powerful," he said, adding that the bomb sent splinters that struck a wall beside him. Police and troops arrived at scene of the attack a few minutes later and transported the dead and injured to hospitals, he said.
Series of bombings
In recent months there have been a series of suicide bombings in Rawalpindi, a city where the army has its headquarters, about 12 kilometers (seven miles) from the capital, Islamabad. President Pervez Musharraf also stays in the city.
On Dec. 27, opposition leader Benazir Bhutto and about 20 others died in a gun and bomb attack in Rawalpindi.
Prior to that, a series of attacks hit security forces and employees of Pakistan's Inter-Services Intelligence agency, including two suicide bombings against a bus of ISI employees and an army checkpoint on Nov. 24 that killed up to 35 people.
There have been no claims of responsibility for the attacks, but authorities have blamed Taliban militants based near the Afghan border who pose a growing security threat across Pakistan.
The latest attack came just a week after a U.S. missile strike killed a top al-Qaida commander, Abu Laith al-Libi, in a remote tribal village near the border with Afghanistan.
Although Pakistan and Washington have not formally confirmed the slaying of al-Libi, Pakistan has since then stepped up security to avoid possible retaliatory attacks by militants.
The killing of al-Libi, described by Pakistani intelligence officials as al-Qaida's operational commander in the border region, was a boost for the U.S. in its battle against the terror network after a spate of pessimistic assessments of the coalition's campaign against the Taliban in Afghanistan.