(CNN) -- A man in a motorcycle detonated explosives Monday near a police van in northwest Pakistan, killing at least six people and wounding more than 30, police said.
The explosion took place on a busy road in the city of Peshawar. No one immediately claimed responsibility for the attack.
It was the latest deadly blast to rattle the country ahead of national elections next month.
On Sunday, at least eight people were killed as the Pakistani Taliban continued to attack candidates in that country's upcoming vote, police said.
In a statement to CNN, the Pakistani Taliban took responsibility for bombings at the offices of candidates in Peshawar and the Orakzai Agency.
Both attacks Sunday targeted independent candidates.
The Taliban said it targeted secular candidates, but many parties have been hit by the increasing violence.
"A man cannot be secular and Muslim at a time. These are two different doctrines in nature," the statement said.
The elections in May will mark the first time in Pakistan's history that one democratically elected government will give way to another.
The nation has experienced three military coups, been ruled by generals for half its life, and it remains mired in near-constant political turmoil.
Pakistani Taliban leader Hakimullah Mehsud has told Pakistanis to stay away from the elections.
"We are not in favor of democracy. Democracy is for Jews and Christians," he said in recent propaganda video.
"We want the implementation of Sharia (law), and for that jihad is necessary," he added.
The Pakistani Taliban are closely linked with the group's namesake in Afghanistan as well as with al Qaeda. It shares a similar religious extremist ideology, but is a distinct group that wants to replace the Pakistani government with an Islamist one.
Ali Dayan Hasan, the Pakistan director at Human Rights Watch, called for the country's interim government to provide candidates with as much protection as possible so they can campaign freely without fear.
"Since the end of military rule in 2008, Pakistan's political parties have displayed an impressive commitment to cementing democratic and constitutional rule," Hasan said.
"It would be a tragedy if a combination of militancy and the government's failure to ensure security compromises the election and sets back Pakistan's progress towards regular, free and fair elections in which all Pakistanis can participate."
CNN's Nic Robertson contributed to this report.