At least 11 factory workers, mostly women, were killed when a three-storey building of a medicine factory collapsed due to a blast in eastern Pakistani city of Lahore on Monday, rescue teams and health officials said. Most parts of the factory, located in populated area of Lahore, the capital of Punjab, caved in when nearly 60 workers were inside the building, spokesman for the rescue team, Karamat Ali, said. There had been conflict reports about the nature of the blast. Rescue teams said a gas cylinder or a boiler may have caused the blast. Ali said that rescue teams and locals pulled 11 bodies and 9 injured out of the rubble in several hours of operation. The injured had been shifted to the city\'s main Jinnah Hospital. The blast ripped through the factory building on Multan Road at 8:15 a.m. (local time), residents said. The factory was manufacturing veterinary medicines. Rescue teams rushed to the site and joined the locals in rescue operation. The Lahore police arrested manager of the factory over casualties. Chief Minister Punjab Province Shehbaz Sharif ordered an inquiry and asked the officials to determine those responsible for the blast. At least 120 rescuers along with officials of town administration and Lahore Solid Waste Management Company had been busy to ensure minimum casualties through a safe and speedy evacuation of the victims, the spokesman said. District Coordination Officer Ahad Cheema told reporters that the factory of veterinary drugs was operating inside the building, adding the factory had been closed three times but the owners had opened it again. The residents of the area told newsmen that the factory had been sealed three years ago on complaints of child labour but the owners managed to resume the work. District Officer Labour Sheikh Sabir said that there was no record of sealing the factory on the complaints of \"child labour\". However, he said the factory may have been sealed on some \" medicine issues\" by the health department. Rescuers said the rescue operation had faced difficulties due to narrow paths, adding that heavy machinery was called to remove the debris.