German Vice Chancellor and Foreign Minister Sigmar Gabriel gives a press conference on July 20, 2017 in Berlin following the arrest of a German human rights activist in Turkey.
Insisting that "people are doing better" than they were four years ago, Angela Merkel made her re-election pitch to a crowd of some 3,000 in a medieval town square in western Germany, a stump speech marred by a clutch of jeering anti-immigration protesters.
Tensions have spiralled between Germany and Turkey in recent months. It was the first visit to Turkey by the head of Iran's military since the 1979 revolution, Turkish media said.
Following the attempted coup, Turkey accused Germany of harboring alleged supporters of US-based cleric Fethullah Gulen, who Turkish authorities claim was the mastermind behind attempts to overthrow the government.More news: Mattis: Any missile threatening Guam would be shot down
Turkey was also angered when Germany provided asylum to Turkish officers allegedly linked to the attempted coup.
Speaking to journalists in Istanbul on Friday, Erdogan said: "I ask all my citizens not to support [major parties] including the Christian Democrats, the SPD or the Greens. Vote for those who don't have enmity towards Turkey", he said.
"Erdogan's interference in Germany's electoral campaign shows that he wants to incite people in Germany against each other", he added.
Erdogan has been increasingly critical of Germany ever since Berlin blocked him from holding campaign rallies in the country ahead of a referendum vote that granted more power to the Turkish president.More news: Jonny Evans would be 'perfect' at Man City - Given
Since a failed coup in July a year ago, tens of thousands of people have been arrested in Turkey - including officials, academics and journalists. "No one who treats Germans in this way can seriously expect us to carry on with our political and economic relations as if everything in the garden were rosy".
"Teach them (the three parties) a lesson in the German elections".
Germans go to the polls on September 24th for elections where Merkel is running for a fourth term.More news: Zimbabwe's first lady remains quiet amid assault claims