At least two policemen were killed and six injured in a suicide attack on a police convoy in Pakistan's northwestern Peshawar city on Thursday, officials said.Senior Superintendent of Police Mian Saeed said that the suicide bomber rammed his explosives-laden motorbike into a vehicle carrying deputy commandant (DC) of Frontier Regiment Police in Hayatabad area of Peshawar, the capital city of Khyber Pakhtunkhwa province.The DC, Malik Tariq, sustained serious injuries and his vehicle was completely destroyed in the blast, Xinhua news agency reported.Tariq was on his way home from office when his convoy came under attack.Police said the bomber, who was carrying about four to six kg of explosives, was also killed in the attack.The injured people have been shifted to Hayatabad Medical Complex.Prime Minister Nawaz Sharif condemned the attack and sought a report from the officials concerned.