PESHAWAR, Pakistan — A suicide bomber in a rickshaw detonated his explosives near a group of policemen in northwest Pakistan's main city of Peshawar on Monday, killing three people, police said.

The attack was the latest in a string of strikes that has killed more than 300 people over the past six weeks. The bloodshed appears aimed at distracting the government from its offensive against the Taliban in the South Waziristan tribal region.

Five other people were wounded in the blast at an intersection on the main road that circles the city, police official Shaukat Khan said. TV footage showed a crane lifting the rickshaw's carcass to clear the road.

The bomber was likely heading to a more crowded area but decided to set off his explosives when police stopped the rickshaw to check it, senior Peshawar police officer Liaquat Ali Khan said.

The attacker killed a police constable, the rickshaw driver and a passer-by, 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."

Peshawar has been struck several times during the recent surge of strikes. A late October explosion in the city leveled a market, killing at least 112 people in the deadliest attack to hit the country since 2007.

Militants have also stepped up attacks in other areas near the Afghan border. A roadside bomb killed two paramilitary troops and wounded a third in Salarzai town in the Bajur tribal region, said a local government official, Abdul Wadood Qureshi.

Also in Bajur, militants shot and killed a senior police officer in the main town of Khar as he was leaving his office, said another local government official, Adalat Khan.

The military concluded a six-month campaign in Bajur earlier this year to clear the area of militants, but periodic attacks have continued and have increased since the army launched its South Waziristan offensive in mid-October.

The government has pledged to press ahead with the offensive despite the assaults. The U.S. supports the South Waziristan operation because Pakistan's tribal belt is home to many militants involved in attacks on Western troops across the border in Afghanistan.

Pakistan's army has pitted some 30,000 troops against up to 8,000 militants, including many Uzbeks and other foreign insurgents who have long taken refuge in the lawless tribal areas.