Russia's healthcare regulator on Wednesday ordered a stop to the use of ventilators believed to have caused two fires at coronavirus hospitals that left six people dead.

Emergencies personnel work at the site of a fire at the Saint George hospital in Saint Petersburg on May 12, 2020. Photo by AFP

The federal regulator Roszdravnadzor "has halted the use on Russian territory of... Aventa-M ventilators produced from April 1, 2020" by a Urals factory, part of the state conglomerate Rostec.

The devices were used to treat patients in hospitals in Moscow and Saint-Petersburg where fires broke out over past week, a statement said.

The fire in Moscow's Spasokukotsky hospital killed one person last week, while a blaze in a medical facility in Saint Petersburg Tuesday left five dead. 

Russia's deputy prime minister overseeing healthcare, Tatiana Golikova, said Tuesday that investigators are looking into the circumstances of the  fires.

Rostec said last month its factories would produce 6,711 ventilators to treat virus patients, though it was not clear how many of these were the Aventa-M model.

The ventilators were also part of a Russian aid shipment to the United States on April 1.

However a spokesman for the US Federal Emergency Management Agency, which received the supplies, told TASS agency that the ventilators have not been used.