Germany's government has condemned the alleged abuse of refugees by security guards at an asylum center.

Police in the western city of Hagen said Sunday they are investigating allegations that guards from a private security company physically and mentally abused refugees.

Evidence included a picture found on a guard's cellphone showing another guard pushing his foot against the neck of a handcuffed refugee lying on the floor.

Government spokesman Steffen Seibert told reporters in Berlin on Monday that "any citizen would be shocked by such pictures and want to know whether what the pictures suggest actually happened."

He called for the allegations to be investigated and those responsible to be punished.

Germany has seen a surge in asylum applications this year, partly because of the war in Syria.