A fire broke out late Saturday at a Moscow hospital treating coronavirus patients, killing one person and forcing the evacuation of patients, Russian state news agencies report.

In a statement, Moscow Mayor Sergey Sobyanin said the blaze occurred at City Clinical Hospital No. 50.

“The fire was quickly extinguished,” he said. “All patients are evacuated and will be transported to other hospitals. Unfortunately, there were some casualties. According to preliminary data, one of the patients died. I express condolences to their family and friends.”

Sobyanin said the causes of the fire would be investigated. Russian state news agency TASS, citing preliminary data, said the fire in an intensive care unit was caused by the malfunction of medical equipment. Five people were saved from the burning ward and 200 were evacuated elsewhere, TASS said.

TASS, citing emergency services, said the fire broke out in a unit with coronavirus patients on Saturday evening.