The remains of 220 people have been found in Hall in Austria's Tirol province in what is believed to be a Nazi mass grave for mental patients subjected to "euthanasia."

The likely mass grave is located in a hospital yard, and is to be excavated in order to determine for sure if the mass grave with people buried in 1942-1945 contains the bodies of actual mental patients killed by the Nazi regime.

The hospital holding company Tilak said it became aware of the possibility during planning to dig up the graveyard in Hall, Tyrol province, to make way for a construction project.

Spokesman Johannes Schwamberger said work on the construction project has been stopped to allow an investigation and to identify the dead.

Even though figures are vary depending on historical research sources, hundreds of thousands of mentally and physically disabled persons are known to have been killed by the Nazis in Germany, Austria, and other locations in the 1930s and during World War II, including through what was described at the time as an "euthanasia program."

The clinic in Hall in operation in the 1940s. Historians assume that 100 to 360 psychiatric patients were killed in the so-called euthanasia program, DPA reported.