Five coronavirus patients were killed in a fire at a hospital in Russia today, Russian state news agencies reported.

The victims were connected to a ventilator on the sixth floor of an intensive care unit at the St. George Hospital in St. Petersburg, state news agency TASS reported. TASS, citing medical personnel, said the patients were seriously ill with coronavirus.

Some 150 people were forced to evacuate from the hospital, according to TASS.

Initial findings suggest the fire may have been caused by a short circuit in the ventilator or its malfunction, state news agencies said.

Russia’s top law-enforcement body, the Investigative Committee, said a criminal investigation had been opened into the matter.

This is the second deadly hospital fire in recent days: On Saturday, a fire broke out in a Moscow hospital treating coronavirus patients, killing one patient and forcing 200 people to be evacuated, Russian state news agencies reported.

TASS, citing preliminary data, said the fire occurred in an intensive care unit due to the malfunction of medical equipment.