Germany's foreign minister welcomed the release on Sunday of a German writer detained in Spain on a Turkish warrant.
Turkish-born writer Dogan Akhanli, who has German citizenship, was arrested Saturday while on holiday in southern Spain.
Mr Akhanli was conditionally released after a court hearing, but ordered to remain in Madrid while Turkey's extradition request is considered, his lawyer said.
It was not immediately clear what Mr Akhanli is accused of, but the author has in the past written about the mass killing of Armenians in Turkey in 1915.
The killings are a sensitive subject in Turkey, which rejects the widespread view that they constituted genocide.
German foreign minister Sigmar Gabriel said in a statement "it would be terrible if Turkey could get people who raise their voice against (Turkish President Recep Tayyip) Erdogan imprisoned on the other side of Europe".
"I have complete faith in Spain's judicial system and know that our friends and partners in the Spanish government understand what's at stake," Mr Gabriel said.
Mr Erdogan hit back while speaking to supporters in Istanbul, attributing Ankara's souring relations with Berlin to next month's German election and warning Germany to "mind its own business".
"They have nothing to do with democracy," Mr Erdogan said, warning Mr Gabriel to "know his place" and to address Turkey's foreign minister instead of its president.
The already-high tensions between the two countries hit another peak on Friday when Mr Erdogan said all of Germany's mainstream parties were enemies of Turkey and urged Turkish-Germans to not vote for them in the forthcoming election.
Mr Akhanli emigrated to Germany in 1991 after spending years in a Turkish prison following the 1984 military coup in the country.
The German section of the writers' association PEN called the arrest warrant against Mr Akhanli politically motivated.
Spain is also holding Turkish-Swedish reporter and writer Hamza Yalcin who was arrested on August 3 in Barcelona on a Turkish warrant for alleged terrorism.
PEN and Reporters Without Borders have demanded his release. The Swedish branch of Reporters Without Borders said Mr Yalcin's arrest was an attempt by Mr Erdogan to show he can reach critical voices abroad.
Spain's Freedom of Information Defence Platform said it welcomed the decision on Mr Akhanli, but reiterated that it expects Mr Yalcin to be let go and Spain to explain both arrests.
German Chancellor Angela Merkel said the arrest of Mr Akhanli was wrong.
"We mustn't abuse international organisations like Interpol for this," she told German broadcaster RTL.
Mrs Merkel called Mr Erdogan's comments "completely unacceptable".
"I invite everyone to vote, here in a free country," she said.
Mrs Merkel said she would work hard to improve prison conditions for a number of Germans currently detained in Turkey on accusations of supporting banned organisations.