AL-KHOBAR — An investigation has been launched to ascertain the cause of a huge fire in a residential complex here which killed at least 11 people and injured more than 200, officials said. The early Sunday morning blaze broke out in the basement of the residential compound known as Radium Residential Complex. It is used by the state oil giant Saudi Aramco. The Interior Ministry's General Directorate of Civil Defense said the casualties involved victims of various nationalities. Some of those injured were in critical condition, the directorate said. It put the number of injured at 219 by early afternoon. Col. Ali Al-Qahtani, Eastern Province Civil Defense spokesman, said evacuation efforts continue to save people from rooftops. Saudi Aramco said some of the injured were treated at the scene, where an emergency command center had been set up, while others were taken to company medical facilities and local hospitals. Emergency response teams at Saudi Aramco continued transportation and evacuation of the injured to Johns Hopkins Health Center in Dhahran and a number of nearby hospitals in cooperation with the Ministry of Health and the authorities concerned, said the Saudi Press Agency. The rapid response teams backed by helicopter, fire-fighting teams and ambulances were pressed into service. Residents affected by the blaze were being moved to alternate accommodation. Saudi Aramco promised to use “all means and available resources” to help those affected. According to Saudi Aramco website, the Radium Residential Complex consists of eight six story buildings and comprises 486 units. Mohammed Siddique, an engineer who lives nearby, told the Associated Press he first saw smoke coming from the complex at around 6 a.m. Emergency crews struggled to contain the blaze. Images posted by witnesses on social media showed thick smoke pouring from the complex as helicopters hovered overhead. “I saw at least 30 ambulances and three helicopters. The smoke was very heavy,” Siddique said. Siddique described the complex, which includes multiple buildings, as relatively new and “nicely built” with a mix of Western, Asian and Saudi residents. It is rented by Aramco and guarded by security teams affiliated with the company, he said.