Germany has warned Russia against politicising a case involving the alleged rape of a German-Russian girl.
The teen, named only as 13-year-old Lisa F, said she was abducted and raped by migrants, but German police have said there is no evidence of either.
Russian Foreign Minister Sergei Lavrov said it was “clear” she had not gone missing voluntarily.
Hitting back, the German government said it was “impermissible” to make political use of the case.
The alleged incident has sparked anti-migrant protests among some in Germany’s Russian community.
German authorities are already under pressure after a wave of sexual assaults over New Year in the city of Cologne, most blamed on migrants.
Accusing Germany of a cover-up in the case of Lisa F, Mr Lavrov said “I hope that these problems are not swept under the carpet”.
But his German counterpart, Frank-Walter Steinmeier, warned against using the case “for political propaganda, and to enflame and influence what is already a difficult debate about migration within Germany”.
“I can only advise the Russian authorities to stick to the findings of the investigation,” he said.
German police concluded that sexual contact was not forced in the case of Lisa F, whose full name is protected for legal reasons.
The age of consent in Germany is 14 and prosecutors are investigating two men for child abuse.
Kremlin-backed media have often been accused of using propaganda to stir up trouble with Russian-speakers living in the Baltics, the BBC’s Damien McGuinness says.
But now some fear the same tactic could be being used in Germany, possibly to keep Chancellor Angela Merkel on the back-foot when it comes to the fate of EU sanctions imposed on Russia because of the conflict in eastern Ukraine, our correspondent adds.