At least four policemen were killed and another 10 people were injured Wednesday as a suicide bomb blast hit a police post in Pakistani northwestern city of Peshawar, police said.

Suicide bombers rammed their explosive-laden vehicle into the police checkpost at Pir Bala in early morning, said Liaquat Ali, Peshawar's chief police officer. Six police and two children were injured.

The injured policemen and bodies of the dead have been shifted to hospitals, hospital sources said.

The chief police officer said the terrorists were bidding to get through the checkpost into the city so it must be seen as a foiled suicide attack, which could prove even worse in case they did not fail to get into city.

The attackers used at least 180 kg explosives, causing damage to adjacent buildings including some shops and a mosque, police said.

The police checkpost has been completely annihilated and rescue efforts are underway. Police said the death toll may rise.