A gunman with suspected far-right links shot dead nine people, some of them migrants from Turkey, in an overnight rampage through a German city before killing himself, officials said.

Chancellor Angela Merkel condemned the attack on two shisha bars in Hanau, near Frankfurt. She told reporters it appeared to have been motivated by the "poison" of racism that was to blame for "too many crimes", as Turkish officials called on her government to respond robustly.

The presumed killer was a 43-year-old German man who held a firearms licence and was a member of a gun club.

Police chased a car used to leave the scene of one shooting to its owner's address, where they found his body and that of his 72-year-old mother, said Peter Beuth, interior minister of Hesse state, where Hanau is located.

Federal prosecutors said they had taken charge of the case due to its likely extremist motive, and newspaper Bild said the suspect had expressed far-right views in a written confession.

In shisha bars, customers share flavored tobacco from a communal hookah, or water pipe. In Western countries, they are often owned and operated by people from the Middle East or South Asia, where use of the hookah is a centuries-old tradition.

Turkey's ambassador in Berlin, Ali Kemal Aydin, told state broadcaster TRT Haber that five Turkish nationals were among the dead.

"We expect German authorities to show maximum effort to enlighten this case. Racism is a collective cancer," Turkish presidency spokesman Ibrahim Kalin said earlier on Twitter.

The Confederation of the Communities of Kurdistan in Germany said several victims were Kurdish, expressing anger that Germany's political leaders "are not resolutely opposing right-wing networks and right-wing terrorism."