At least 21 people, including half a dozen policemen, were killed in a suicide car bombing on a security checkpoint in violence-hit north-west Pakistan, officials and hospital authorities said, dpa reported.
The attack took place at Zangali check post, 15 kilometres from Peshawar, capital of North West Frontier Province, local police chief Muhammad Suleman said.
"We received 17 bodies and 67 injured," Khizar Hayat, the top official at Peshawar's Lady Reading Hospital told Deutsche Presse- Agentur dpa.
Six policemen checking vehicles at the cordon were also among the dead. Four more bodies were recovered later in the day from the rubble of the two building flattened by the high-intensity blast.
Javed Afridi, a local journalist and witness to the incident, said the blast occurred when the law enforcers tried to stop a double-cabin pickup truck at the security barrier set up on a main road connecting Peshawar with key towns in the south.
The explosion destroyed the check post and several vehicles, including an armoured personnel carrier.
Television footage showed utter destruction around the site of the blast, which left a vcrate over two metres wide and a metre deep.
A large number of people were trapped in the rubble and could be pulled out only after hectic efforts by the locals as the authorities response was very slow.
Doctors feared that the death toll would increase as more than 30 of the blast victims had suffered critical wounds, mostly caused by flying shrapnel.
Security officials said the suicide bomber might have been pursuing a more important target in Peshawar where lawmakers were voting in the country's crucial presidential elections, adding that he detonated the explosive after failing to cross the check post.
Though no group immediately claimed the responsibility for the deadly attack, many believed it was carried out by pro-Taliban militants in the semi-autonomous tribal region bordering the provincial capital.
The fact that the explosive-laden truck was moving towards Peshawar from the volatile town of Darra Adamkhel gave credence to the possibility.
Government troops are engaged in clashes with the militants in Darra Adamkhel, a known market of locally-produced weapons, and had killed more than two dozen rebels in this week.
The fighting erupted last week after the militants carried out a failed suicide car bombing on a paramilitary camp in the area. Two civilians were killed and 30 others, including 20 Frontier Corps troops, were wounded when the vehicle blew up after being fired upon by the soldiers.