A police constable was killed while five others were injured in a blast at a checkpost near Mardan's Chamtar area in Khyber Pakhtunkhwa on Thursday, police said.

District Police Officer (DPO) Irfanullah Khan told Dawn.com the explosion took place at approximately 10:45am.

The DPO said unknown "terrorists" planted a device beneath a bridge adjacent to the checkpost's gate. As a result, a constable was martyred, while three other policemen and two citizens were injured.

The intensity of the blast damaged the gate of the checkpost and the windows of nearby buildings.

SP Operations Shah Mumtaz said that it was a "remote-controlled blast", adding that the terrorists were targeting a police vehicle.

Rescue officials rushed to the scene after receiving information about the incident, and transferred the injured and the deceased to the Mardan Medical Complex.

The DPO later visited the injured at the hospital and also inspected the site of the blast. Security in the area was beefed up after the incident.

The Mardan Counter Terrorism Department (CTD) registered a case against unidentified suspects. According to the CTD, around eight to 10 kilogrammes of explosives were used in the blast.

Separately, Awami National Party provincial president Aimal Wali Khan strongly condemned the attack.

"Our condolences go out to the family of the martyred police [constable]. The ANP has repeatedly warned about the new wave of terrorism but no seriousness has been shown in this regard. Police and the public are paying the price for that," he said.