Militants who attacked a police facility in the heart of Pakistan's largest city were attempting to free comrades they believed were detained there, a senior minister said Friday. The coordinated assault late Thursday in Karachi, using a car bomb and guns showed the ability of militants to strike back. A gang of around six gunmen managed to penetrate a high-security area of Karachi. They opened fire on the offices of the Crime Investigation Department before detonating a huge car bomb that leveled the building and others nearby. The police offices housed a detention facility that was believed to be holding criminals. The CID takes the lead in hunting down terrorists in Karachi. Earlier this week, the agency arrested six members of Lashkar-e-Jhangvi, an Al-Qaida linked group blamed for several high profile attacks in recent years. The suspects were presented before a court earlier Thursday. - Photos by Hasaan Haider/Dawn.com and Saboor Haider.