Germany on Wednesday warned Russia against "exploiting" a murky case involving an alleged rape of a German-Russian teenager in Berlin after Moscow accused police of a cover-up.

After Berlin police last week rejected the 13-year-old's account that she was sexually assaulted by "foreigners", Russian Foreign Minister Sergei Lavrov on Tuesday lent credence to the girl's allegations and charged that her disappearance had been "hidden".

Government spokesman Steffen Seibert on Wednesday hit back, saying "there is no reason, in fact it is unacceptable, for this incident to be politically exploited."