Five people, including three policemen, were killed when a bomb apparently targeting a police party exploded in northwestern Pakistan, police said on Saturday.
The remote-controlled device, planted on a bicycle detonated late Friday in Dera Ismail Khan town, local police chief Ghaffar Qaisarani told AFP.
The bicycle was parked near an open place where another bomb had earlier exploded harmlessly, he said.
The bicycle bomb exploded soon after a police party arrived to investigate the incident, he said.
More than a dozen people were wounded including nine policemen, he said.
"It appears the police party was the target," he said.
No group has so far claimed responsibility of the attack.
Qaisarani believed the blast could be linked to the unrest in North West Frontier Province and the rugged tribal terrain bordering Afghanistan.
Dera Ismail Khan was already in the grip of sectarian tension after recent clashes between militants from the majority Sunni and the minority Shiite Muslim communities.
Pakistan has suffered a spate of attacks in recent days despite ongoing peace talks between the new government, which took power in March, and Islamic militants based in the lawless northwestern tribal regions.
Friday's blast came days after a suicide car bombing outside the embassy of Denmark in Islamabad on Monday which killed six people including a Danish citizen.
Al-Qaeda claimed in Internet statements Wednesday to have carried out the attack in revenge for the publication in Danish newspapers of cartoons insulting the Prophet Mohammed, SITE monitoring services said.