Amid a sharp rise in threats to the political elite, one politician has already died. Reports suggest that such attacks are becoming more common.

Dieter Gummer, a member of the notoriously pro-migrant left-wing Social Democratic Party, answered his door on Monday evening to find an unfamiliar face outside. The visitor heavily punched the 67-year-old politician in the face, according to police in nearby Ludwigshafen.

Gummer fell on the floor and hit his head, requiring treatment in hospital. The culprit fled the scene. The attacker was unknown to the mayor and is described by police as a man of slim build, around 40 years old, with dark skin. Police in the southern German town says they're baffled as to the motive and are "investigating in all directions."