A suicide bombing targeting police officers in northwest Pakistan has killed four people; three officers and one civilian, officials said.

The attacker struck near a police van in Peshawar on Monday, killing Rasheed Khan, a deputy superintendent, two other policemen and a passerby, and wounding at least six others.

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

According to a police officer at the scene, the attack was carried out by a teenage boy carrying between six and seven kilos of explosives.

The Pakistani Taliban has claimed the bombing.

"We have already announced that we will target police and security forces," Azam Tariq, a spokesman for the Tehreek-e-Taliban Pakistan told AFP.

Bashi Bilo, senior minister of the northwestern Khyber Pakhtunkhwa province, said fighters were "targeting police to pressure and dishearten them".

But he added that such attacks would not weaken the government's resolve to combat such attacks.

Meanwhile the AP news agency reported that a second blast hit a roadside police patrol several miles from the first incident, killing at least one policeman and wounding three others.

Pakistan's northwest and tribal areas have been wracked by violence, mostly targeting security officials, since hundreds of Taliban and al-Qaeda fighters sought refuge there after the US-led invasion of Afghanistan in 2001.

Peshawar is located next to Pakistan's tribal area, which fighters use as their main base of operations.

Source: Agencies