By Faris Ali
PESHAWAR, Pakistan (Reuters) - A suicide bomber drove an explosives-packed car into a police station on Wednesday as the Taliban intensified attacks against Pakistan's security forces after the killing of al Qaeda's Osama bin Laden.
At least five policemen and a soldier were killed in the attack in the northwestern city of Peshawar. The Pakistani Taliban said they were responsible.
The militants, allied with al Qaeda, have vowed to avenge bin Laden's killing by U.S. forces in a Pakistani town on May 2.
"We will continue attacks on security forces until an Islamic system is implemented in Pakistan, because the Pakistani system is un-Islamic," Ehsanhullah Ehsan, a spokesman for the Pakistan Taliban, told Reuters, adding the attack was also in revenge for bin Laden's death.
The blast came two days after a brazen Taliban raid on a heavily guarded naval base in the southern city of Karachi that killed 10 military personnel and destroyed two aircraft.
The police station, in a military neighborhood, houses an office of the Criminal Investigation Department, which is responsible for investigating Islamist militants.
There is also a training facility for special forces and officers' residences nearby.
Senior provincial minister Bashir Bilour said up to 300 kg (660 lb) of explosives were used in the bomb that police said wounded 22 people.
Residents said the explosion rattled windows throughout the city. By midday, volunteers and rescue workers were removing rubble with spades, while bulldozers removed broken slabs of concrete.
Senior police officer Ejaz Khan said the bomber rammed his car into the station's gate, on the main road leading to Afghanistan through the Khyber Pass.
Another police officer said about 20 policemen were in the building when the attack happened.
"Three of our colleagues are still missing under the rubble and it will take another hour to clear the site," said officer Bahadur Khan.
"My colleague and I were on the roof, calling for dawn prayers, when all of a sudden there was a big explosion," said wounded policeman Muzaffar Khan. "We don't know what happened but the roof collapsed and we fell on the ground.
"I was trapped in the debris," he said. "I was screaming and crying for help. I was lucky that people pulled me out."
MILITARY UNDER PRESSURE
The police station is about a km (half a mile) from the U.S. consulate and in the same area where Taliban militants detonated a car bomb last week targeting a consular convoy.
One man was killed and about a dozen people were wounded, including two U.S. nationals, in that attack.
The commander of the naval base attacked by militants on Sunday was relieved of his command, the Navy said in a statement on Wednesday, a rare sign of accountability in the powerful military establishment.
"Commodore Raja Tahir has been relieved from his duties with immediate effect," it said adding an inquiry had been ordered to investigate the attack.
The string of attacks by al Qaeda-linked militants has raised concern about the possible presence of Islamist sympathizers within the military, which controls Pakistan's nuclear weapons.
A 2008 U.S. diplomatic cable released by WikiLeaks revealed U.S. concern that officers at a prestigious army institution were largely biased against the United States, a key ally which has given Pakistan more than $20 billion in aid over the past decade, about two-thirds of it military.
The military is also facing accusations of either incompetence, or possibly complicity, after it became clear that bin Laden had been hiding out in Abbottabad, a garrison town north of the capital, for several years before he was shot dead by U.S. forces.
After bin Laden's killing, some Pakistanis have questioned whether the funding for the military is really worth it. Pakistan spent 442.2 billion rupees ($5.15 billion), about 20 percent of its 2010/11 budget, on defense last year -- an increase of 17 percent from the year before.
This year it plans to spend 495 billion rupees ($5.76 billion), officials say.
"To me, it defies logic for allocating so much on defense," said Asad Shafqat, a banker in Karachi.
The government showed no signs of even light criticisms of the powerful military establishment. Prime Minister Yusuf Raza Gilani expressed "full support" for the armed forces.
Experts said changes in defense spending were unlikely.
"The balance between defense and social development has to change but I don't see that happening in the short term," said Shafqat Mahmood, a political analyst based in Lahore.
"Recent events have shown that we have to improve our defense and vulnerabilities."
(Additional reporting by Sahar Ahmed, Zeeshan Haider, Kamran Haider, Augustine Anthony, Haji Mujtaba and Saud Mehsud; Editing by Chris Allbritton and Robert Birsel)