Karachi, Feb 18 : An inquiry report prepared by the bomb disposal squad on the Karachi Police Office (KPO) attack revealed that each of the six to 10 terrorists, who stormed the building, carried almost 8 kg of explosive material in their suicide vests. Right after the incident on Friday night, the bomb disposal team prepared a detailed report behind the happenings at the crime scene. As per the report, the attackers had been wearing explosive vests, out of which one had been detonated by the bomber; while two had been defused by the squad, Samaa TV reported. It added that seven to eight kgs of explosives had been used in each suicide vest, following the intensity of blast recorded after one of the bombers detonated his jacket on the fourth floor. The explosion damaged the building structure while the windows of the nearby buildings also shattered, Samaa TV reported. The report stated that the police officials recovered a white vehicle from the scene and seized ammunition hidden inside it. While, there is no such record of the car being stolen by someone or the terrorists. Two terrorists have been identified as Kifayatullah who hailed from Lucky Marwat while Zalnur hailed from North Waziristan, Samaa TV reported. Militants wearing suicide vests and carrying automatic weapons and grenades stormed the Karachi Police Office (KPO) on Friday. A gun battle raged for more than three hours following the assault after dusk, as security forces went floor-to-floor through the building in pursuit of the assailants. The forces retook the building after killing the three militants, a government spokesperson said, The Express Tribune reported. The attack, claimed by the Tehreek-e-Taliban Pakistan (TTP), came just weeks after a bomb blast at a police mosque in Peshawar killed over 100 people, mostly policemen. Officials said late on Friday that security would be stepped up in Islamabad, Express Tribune reported. The tightly guarded KPO is located behind the Saddar police station on Sharea Faisal. The compound is home to dozens of administrative and residential buildings as well as hundreds of officers and their families. The attack began between 7 p.m. and 7.30 p.m. on Friday. The terrorists, reportedly drove a silver-coloured vehicle to reach the Saddar Police Lines behind the KPO. The assailants first entered a local mosque near the KPO under the cover of indiscriminate fire. The imam of the mosque told The Express Tribune that he had concluded the Maghrib prayers, when he heard the gunshots. He added that as soon as he came out of the mosque, the terrorists opened fire at him but he managed to escape. A sweeper lost his life due to firing by the terrorists there, officials said later. The terrorists then reached the KPO premises and entered the building. The police said the attackers used more than 20 hand grenades during the assault. As soon as the incident was reported, police, Rangers and the Special Security Unit, officers from other agencies and trained commandos reached the spot. Sharea Faisal was closed for traffic, while electricity supply was also cut off in the area, Express Tribune reported. During the initial operation, a terrorist wearing a suicide jacket blew himself up on the fourth floor of the building. After that, the police and Rangers commandos started searching the upper floors of the building. During that time, the area reverberated with heavy gunfire and loud explosions from inside the compound. Finally, the terrorists reached the roof of the building where they hunkered down until they were killed by the Rangers and police commandos in a tough battle, Express Tribune reported. Karachi South Deputy Inspector General of Police Irfan Baloch said up to 30 policemen were present at the time of the attack. He added the terrorists carried hand grenades and Kalashnikovs, besides gram, dates, water bottles and other items. The car in which the terrorists had come was left running throughout the operation. The police later recovered an Ajrak, a mat, slippers, water bottles, a number plate placed on the dashboard and a magazine, Express Tribune reported. /IANS