Istanbul - Turkey's football chief on Tuesday condemned as "slanderous" and "unacceptable" German criticism of a meeting between top players of Turkish origin in Britain's Premier League and President Recep Tayyip Erdogan.
Germany internationals Mesut Ozil of Arsenal and Ilkay Gundogan of Manchester City met Erdogan late Sunday during his three-day visit to Britain.
Pictures of the meeting in London were then posted on the official Twitter account of Erdogan's ruling Justice and Development Party (AKP) ahead of June 24 presidential and parliamentary elections.
German Football Association (DFB) president Reinhard Grindel responded that international players should not let themselves be "manipulated" in Erdogan's election campaign.
"I think they know they made a mistake, we have to deal with it now," added Grindel in Dortmund after the pair were named in Germany's provisional 27-man World Cup squad.
But Turkish Football Federation (TFF) chairman Yildirim Demiroren hit back by saying he had read Grindel's "slanderous" postings "with great sadness".
"The thoughts expressed by the DFB president are absolutely unacceptable," Demiroren said in a TFF statement.
He described Erdogan, a footballer in his youth, as a "passionate football fan" and someone who had made a huge contribution to the game in Turkey.
"So it's completely normal that he meets three Turkish-origin footballers born in Germany," Demiroren added. "This would be normal in any nation... if a footballer was invited by the president."
As well as Ozil and Gundogan, who were both born in the German city of Gelsenkirchen, also present was striker Cenk Tosun of Everton who was born in the German town of Wetzlar but represents Turkey.
All three players handed over souvenir signed club shirts to the president. "To my dear president, with my respects," Gundogan wrote on his.
Demiroren said that Grindel had made a "terrible mistake" by allowing politics to infect sport and implied it could be a tactic in the race between Turkey and Germany to host the Euro 2024 tournament.
"The Turkish Football Federation will engage in no such behaviour and will continue its bid for Euro 2024 to the end within the rules of UEFA," he said.
Gundogan insisted after the controversy he "didn't want to make a political statement with this photo and even less so campaign" in the election.
But the images caused a furore in Germany, with lawmaker Cem Ozdemir, himself of Turkish origin, reminding the players that "the president of an international German footballer is called Frank-Walter Steinmeier," referring to the German head of state.
Germany's World Cup-winning head coach Joachim Loew said he had limited sympathy.
"From the DFB's perspective, it has been made clear that it was not a good decision," said Loew.
"But I have a bit of understanding that two hearts beat in the chests of players with an immigration background.
"It's not always easy, the players have expressed regret and done a lot for integration in Germany, they have good character.
"We will talk about it in the training camp," added Loew with the German squad to meet in north Italy next week to finalise their World Cup preparations.