MOSCOW — The Russian foreign minister, Sergey V. Lavrov, on Thursday dismissed what he called Germany’s accusations that Russia was exploiting the mysterious disappearance of a 13-year-old Russian-German girl, who lives in eastern Berlin, to pursue its political aims.

Russia’s prime state TV station, Channel One, brought up the case last week. The report identified the girl only as Liza and said her 30-hour disappearance had been reported on Jan. 11. Her relatives claimed that she had been kidnapped and raped by three migrants. Instead of opening a criminal case based on the allegations, the police “covered them up,” a man, identified as the girl’s uncle, told Russian television.

But Berlin police who investigated the case and examined the girl have rejected her account of being abducted and forced to have sex. State prosecutors are reportedly investigating at least one suspect on possible charges of having sex with the girl, who is under the age of consent, which in Germany is 14. If charges are brought, it is not clear whether they would be statutory rape or child abuse.

The case has riled the Russian-language Internet, with many commentators using it to suggest — sometimes in almost abusive terms — that Germany is failing to act against the dangers posed by hundreds of thousands of new migrants. Last week, several demonstrations were held around Germany by Russian-speaking Germans claiming that they felt unsafe.