German far-right politician Frank Magnitz has been beaten up and severely injured in an attack seen by police as politically motivated.
The leader of Alternative for Germany (AfD) in Bremen was attacked by three people in the centre of the northern city on Monday.
Masked men knocked him unconscious with a piece of wood and kicked him in the head, AfD officials said.
They praised a construction worker for coming to his aid.
Mr Magnitz had just left a new year reception in Bremen’s Kunsthalle art museum when he was attacked.
AfD entered the national parliament (Bundestag) for the first time last year with 94 seats and now has representatives in every German state parliament.
Party spokesman Jörg Meuthen tweeted a photo of Mr Magnitz lying unconscious in his hospital bed and said he had been left “half-dead”.
He had a big gash on his forehead and severe bruising around his right eye.
Last week an AfD office in the eastern town of Döbeln was damaged by an explosion. No-one was hurt.