Firefighters with breathing apparatus and a ladder truck work at the Marienkrankenhaus hospital this morning (Picture: AP)

Three patients have been killed and many people injured in a fire that broke out overnight at a hospital in Germany.

Authorities said two people remain critically ill after the blaze in the Marienkrankenhaus hospital,in the Hohenfelde district of Hamburg.

It broke out in a room in the geriatric ward,on the ground floor of the building,and spread to the facade of the floor above. Smoke spread across the building’s four floors.

‘Several people were at the windows calling for help,’ a fire department spokesperson was quoted as saying by German newspaper Bild.

Photo showed elderly patients being rescued with turntable ladders,portable ladders.

Local media reported that some had to be pushed down corridors in wheelchairs while wearing ‘escape hoods’,which give protection from smoke and toxic gases.

Firefighters wearing breathing apparatus work in a burnt-out room on the ground floor (Picture: AP)

The fire department said three adult patients were killed and more than 50 people injured,the German news agency dpa reported.

Of those,two were in a life-threatening condition,16 had serious injuries and 36 were slightly hurt.

A section of the hospital had to be evacuated,and injured patients were treated either at the hospital itself or in nearby clinics.

The fire was extinguished within about 20 minutes. It was not immediately clear what caused it.

With around 600 beds and treating some 93,000 patients each year,the Marienkrankenhaus claims to be one of the biggest Catholic hospitals in northern Germany.