A Pakistani security official examines the wreckage of a rickshaw at the site of a suicide bombing Monday in Peshawar, Pakistan. ((Mohammad Sajjad/Associated Press))

A suicide bomber detonated his explosives near a group of police officers in the northwest Pakistan city of Peshawar on Monday, killing three other people and injuring five.

The attack occurred at an intersection on the main road that circles the city. A senior Peshawar police official said the bomber was riding aboard a motorized rickshaw and was likely headed toward a more populated area when police stopped the rickshaw to check it.

In addition to the attacker, the bomb killed a police officer, the rickshaw driver and a passerby, police said.

"Despite all the security arrangements you cannot stop one who is bent upon killing himself and others," said Sahibzada Anis, a local government official.

"Our police are rendering their lives to save citizens but these kinds of incidents are hard to stop."

The attack is the latest in a string of attacks in Pakistan that has killed more than 300 people in the last six weeks. The attacks are believed to be in retaliation for the government's military offensive against the Taliban in the South Waziristan tribal region.

Peshawar a target of frequent attacks

It comes a day after another suicide bomber killed 12 people and injured at least 25 in the town of Adazai, about 15 kilometres south of Peshawar.

Peshawar, the main city in Pakistan's northwest, has been a frequent site for insurgent attacks. A bomb exploded in a crowded market killed at least 112 in October, in the deadliest attack in the country since 2007.

Pakistan launched its military offensive in mid-October in an effort to hit the Taliban and local insurgents at what was believed to be their main base of operations, near the Afghanistan-Pakistan border in South Waziristan.

About 30,000 troops have been mobilized against militants believed to number about 8,000, with fighting mostly localized in three main Taliban bases, according to army officials. Pakistan has blocked access to the battle zone, however, making independent verification of reported casualties in the fighting impossible.

With files from the Associated Press