At least 11 people were killed and more than 200 injured, many critically, after a blaze broke out Sunday in the basement of the Radium Residential Complex in the Saudi Arabian city of Khobar, the Wall Street Journal reported. The fire soon spread throughout the building, trapping some on rooftops and others in their apartments, the Associated Press reported, citing Saudi officials.

The complex is used by the state oil giant Saudi Aramco to house employees. The blaze’s victims included people of multiple nationalities, according to AP's account of a statement by the Interior Ministry's general directorate of civil defense. The number of injuries was 219 at last report.

Mohammed Siddique, an engineer who lives close to the complex, told AP he first saw smoke Sunday at about 6 a.m. local time (Saturday at about 11 p.m. EDT). A number of images posted on social media by media outlets and witnesses showed thick smoke rising from the complex as helicopters hovered overhead. The photographs showed the smoke billowing from multiple structures in and around what appeared to be the Radium complex, while individuals on the ground were running for safety.

"I saw at least 30 ambulances and three helicopters. The smoke was very heavy," Siddique told AP.

Helicopters were still battling the blaze at 7 a.m. EDT, according to BBC News, which reported that Saudi Aramco has launched an investigation into the cause of the fire, pledging to use "all means and available resources" to help those affected. The company indicated residents affected by the blaze were being moved to alternate accommodations, BBC News said.

The complex is a gated community with eight six-story buildings and a total of 486 units, according to Saudi Aramco’s website. The company employs more than 61,000 workers from 77 countries, many of whom live in company housing.

Some of those injured were treated at the scene, AP reported, citing Saudi Aramco. It added that an emergency command center had been set up and that people injured in the blaze have been taken to company medical facilities and local hospitals. The firm declined to identify the nationalities of the employees killed or injured in the fire.