Turkey president Recep Tayyip Erdogan condemned the "unacceptable" treatment of Mesut Ozil by the Germany football federation on Tuesday.
The Arsenal playmaker felt he was made a scapegoat for Germany's poor showing at the World Cup in Russia after a meeting with Erdogan in London.
"Such racist treatment towards a young man who has given his all to the German national team for his religious beliefs is unacceptable," Erdogan told reporters in parliament.
"Furthermore, how do you explain being unable to tolerate Mesut, Ilkay [Gundogan] and Cenk Tosun taking a photograph in London out of respect of their Turkish roots?
"There are some that could not stomach this, but there are established, responsible politicians who are standing with Mesut."
Ozil, Manchester City midfielder Ilkay Gundogan and Everton striker Cenk Tosun met Erdogan during the Turkish president's three-day trip to England in May. All three players, born in Germany of Turkish descent, presented Erdogan with a shirt from their respective club and took a photo with him.
The photograph sparked months of controversy in the lead-up to the World Cup, both because of Erdogan's autocratic policies and because Ozil and Gundogan were set to represent Germany. Most of the criticism fell on Ozil after Gundogan released a statement explaining his part in the photo, but the Arsenal man stayed silent.
The row has now spilled over to the Turkish town, Devrek, where Ozil's family originate from.
Authorities in the town have removed a street sign on "Mesut Ozil Avenue' of the playmaker wearing a Germany national team jersey. The photograph that initially sparked the controversy featuring Ozil and Erdogan has been erected in its place.
Also on Tuesday, the Turkish Football Federation released a statement supporting Ozil.
"The TFF offers its full support to Mesut Ozil and his family and we condemn the treatment, threats and derogatory messages that he has received because of his heritage and background. Every player, no matter whether they are in the public eye or not, has a right to be protected from abuse, discrimination and messages expressing hate.
"All members of the global football community must be united in our continued efforts to drive out racism and intolerance -- and we must work together to ensure football can realise its potential to achieve positive social impact that promotes the values of inclusivity and respect."