DUBAI, United Arab Emirates (AP) — A large fire broke out yesterday in the basement of a sprawling residential complex in Saudi Arabia’s oil-rich east, killing at least 11 people and injuring more than 200, officials in the kingdom said.

The blaze began early in the morning in a multistory residential compound known as Radium in the eastern city of Khobar. The complex houses workers for state oil giant Saudi Aramco, which oversees petroleum production in the OPEC powerhouse.

The company said an investigation has begun into the cause of the fire, which sent thick black smoke billowing from the pink-and-tan coloured building.

The Interior Ministry’s General Directorate of Civil Defense said victims were of various nationalities, without elaborating. Like many companies in the Gulf, Aramco relies heavily on foreign professionals and other migrant workers.

Some of the 219 people reported injured were in critical condition, the directorate said.

Mohammed Siddique, an engineer who lives nearby, told The Associated Press he first saw smoke coming from the complex at around 6 am. Emergency crews struggled for hours to contain the blaze, which authorities said was under control by mid-afternoon.

“The smoke was very heavy,” Siddique said. He counted at least 30 ambulances and three helicopters responding to the fire soon after it began.

Aramco said some of those hurt were treated at the scene, where an emergency command center was set up, while others were taken to company medical facilities and local hospitals.

The Radium complex is a gated community of eight six-storey buildings with a total of 486 residential units as well as swimming pools and other leisure facilities, according to Aramco’s website.

Siddique described the complex as relatively new and “nicely built,” with a mix of Western, Asian and Saudi residents. It is rented by Aramco and is guarded by security teams affiliated with the company, he said.

Residents affected by the blaze were being moved to alternate accommodation. Aramco promised to use “all means and available resources” to help those affected.

Khobar was the site of a 1996 truck bombing at a dormitory for US Air Force personnel that killed 19 Americans and wounded 372. The man described as the mastermind of the attack, Ahmed al-Mughassil, was arrested after a nearly two-decade manhunt, American and Saudi officials said last week. The FBI has described him as the head of the armed wing of the Saudi Hezbollah group.