At least 22 mental health patients have been killed and about 23 others were injured in a fire at a psychiatric hospital in southwest Russia Saturday.

Nearly 70 patients and at least four hospital staff were inside the building when the fire started late Saturday at a neurological hospital care home in the village of Alferovka in Voronezh, according to RT.

"For the moment, 22 people are dead, two of them died at hospital. Rescuers are searching for another missing person. Four medial workers managed to escape fire. They had helped taking 51 people out of the burning building," The Russian Emergencies Ministry's regional centre told TASS news agency.

"Most dead bodies have been found in places where bedridden patients or patients who took strong drugs had undergone treatment," the ministry said.

About 55 patients have been evacuated, and two people are still reportedly missing. At least two dozen people were admitted to a local hospital with serious burn injuries.

"Twenty-two persons were hospitalized in the aftermath of the fire in the neuropsychiatric hospital in the Voronezh region, all of them reported to be in critical condition," Igor Banin of the Voronezh regional hospital said, according to Sputnik.

Authorities have also launched an investigation into the tragic incident and are looking at a malfunction in the electric wiring system as a possible cause.

A fire at a mental health hospital in northwest Russia left 37 patients dead in September 2013, while a blaze at another mental health institution near Moscow killed 38 people in April that same year, BBC News reported.