At least two policemen were killed and one other was injured on early Thursday morning when some unknown assailants attacked police personnel in Pakistan\'s southern port city of Karachi, local media and officials said. Superintendent of Police Irfan Baloch said that the incident took place when some unknown terrorists opened fire at three policemen when they were sitting at a restaurant for tea in the city. One alleged attacker was also killed in the attack when the injured policeman retaliated with firing. The attacker killed in the shooting could not be identified yet. The attackers who reached the restaurant on motorcycles managed to escape after the attack. The dead and wounded were shifted to the Abbasi Shaheed Hospital of the city. According to hospital sources, the condition of the injured policeman was stable after he went through a successful surgical operation. No group claimed responsibility for the attack yet. Police has become a soft target in Pakistan\'s port city of Karachi as at least 142 policemen including a couple of officers had been killed so far since the start of this year. On Oct. 9, three police officers including a Station House Officer (SHO), Station Investigation Officer (SIO) and a Sub- Inspector were shot dead in the northern part of the city.