One person has died in a fire at a hospital in Russia's second city Saint Petersburg, emergencies services and hospital staff said Wednesday.

Bedsheets caught on fire in one of the buildings of the Botkin hospital around 6am (0300 GMT), first responders said.

"The patient was alone in the room. There were no open flames, but he was poisoned by the smoke," local emergencies services spokesman Andrei Litovko told AFP.

Efforts to resuscitate the man were unsuccessful, he said, adding that the patient was not being treated for the coronavirus.

News agencies quoted sources as saying the patient had been smoking in bed.

Several people died last month in fires at hospitals in Moscow and Saint Petersburg, with faulty ventilators believed to have sparked the blazes, though an investigation is ongoing.

The Botkin hospital for infectious diseases is Saint Petersburg's main coronavirus treatment centre and one of the largest infection facilities in the country.