A fire at an oil workers’ residential compound in Saudi Arabia broke out on Sunday, killing 11 people and injuring over 200 others, reported Reuters.

“At 05:45 today a fire was reported in the basement of the Radium residential compound in Al Khobar which is leased by Saudi Aramco for its employees,” Aramco said in a statement, adding that the cause of the fire was not known.

Aramco has not identified the nationalities of its employees.

According to BBC News Aramco says it has begun an investigation while Saudi officials have admitted that multiple nationalities were among the injured, some in critical condition.

The Civil Defence Department said the fire was under control after tweeting that “Cars and furniture caught fire in the basement of one of the towers, heavy smoke billowed, obstructing rescue and firefighting operations.”