Peshawar, Pakistan  - At least 30 people were killed and more than 80 injured in a suicide car bombing on a security checkpoint on Saturday in north-west Pakistan, officials and hospital authorities said.

The attack took place at Zangali checkpoint, 15 kilometres from Peshawar, the capital of North West Frontier Province, local police chief Muhammad Suleman said.

"So far 30 people are confirmed dead and more than 80 injured while two policemen checking vehicles at the cordon are missing," he added. Earlier some security officials said six policemen were among the dead.

Many people died when two buildings were flattened by the high-intensity blast.

Javed Afridi, a local journalist and witness to the incident, said the blast occurred when the police tried to stop a pickup truck at the security barrier set up on a main road connecting Peshawar with key towns in the south.

The explosion destroyed the checkpoint and several vehicles, including an armoured personnel carrier.

Television footage showed utter destruction around the site of the blast, which left a crater over two metres wide and a metre deep.

A large number of people were trapped in the rubble of the collapsed buildings.

Doctors feared that the death toll would increase as more than 20 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.

A spokesman of local Taliban in the semi-autonomous tribal town of Darra Adamkhel claimed the responsibility for the attack.

"They (security forces) are targeting us with the bombs even in the holy month of Ramadan. We will carry out more such attacks to avenge their brutal actions," Mohammad told journalists by telephone from an undisclosed location.

Government troops have recently been engaged in clashes with the militants in Darra Adamkhel, a known market for 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. (dpa)