The suicide attack, which killed five people and left 11 injured, was claimed by the Taliban, saying it targeted the police in the troubled city of Peshawar.

The police van was on a routine patrol on the outskirts of the city when it came under attack, senior administration official Siraj Ahmed told AFP.

"The bomber was a teenager, he came on foot and blew himself up near the police van," Ahmed said.

The attack killed three policemen -- deputy superintendent Rashid Khan, his security guard and driver -- while two civilians also died in the blast, officials said.

"We have received four bodies -- three police officials and one civilian," the head of Peshawar's main hospital Abdul Hameed Afridi told AFP.

One more person later died of his injuries in the hospital, he said, adding that another seven of the injured were in a serious condition in hospital.

Umar Gul, a police officer at the scene, confirmed the suicide attack.

"We have recovered his head, the bomber was a young boy," he said.

A bomb disposal squad official said the bomber was carrying six to seven kilograms (13-15 pounds) of explosives, which destroyed the police van.

Another police official was killed and three officers wounded when a roadside bomb went off a short time later near a police van in the suburbs of Peshawar, police officer Ejaz Khan said.

The Taliban claimed responsibility for the suicide attack.

"We have already announced that we will target police and security forces," TTP spokesman Azam Tariq said in a telephone call to AFP from an undisclosed location.

The senior minister of the Khyber Pakhtunkhwa province, Bashir Bilor, said militants were "targeting police to pressure and dishearten them".

But he told reporters such attacks would not weaken the government's commitment to combat militancy.

"We will continue our fight against terrorism. We will not be deterred, it will only strengthen our resolve to eliminate terrorists," he added.