Islamabad, July 5 (IANS): At least three people were killed and eight others injured when a blast went off in Pakistan's northwest Khyber Pakhtunkhwa province on Friday, the police said.

The blast took place on a bridge in the Takht-i-Bahi area of Mardan district of the province, killing three people while injuring eight others, including policemen, District Police Officer Mardan Zahoor Babar Afridi told the media.

He said that police officials were the target of the blast as the explosion happened after a police vehicle passed over the bridge, adding that according to a preliminary investigation, an improvised explosive device was planted on the bridge, Xinhua news agency reported.

Rescue teams, police, and security forces immediately reached the site following the blast and shifted the injured to a nearby hospital. The area has been cordoned off while a search operation is underway to arrest the culprits.

No group has claimed responsibility for the attack yet.

Earlier on Thursday, five people, including a former member of the Senate, were killed in an explosion in Bajaur district of the province.