The house in southern Germany where Pope Benedict XVI was born has been vandalized with obscene graffiti, police say.

Someone found the 30-centimetre-high blue letters early Tuesday on the wall over the door of the house in the town of Marktl, they say.

Police spokesman Andreas Guske told The Associated Press that authorities will not release the exact words, but "it was a defaming remark from the realm of the obscene."

He said the words were not specifically directed against the Pope, who has been fiercely criticized recently for his role in what critics allege is a church-wide coverup of sexual abuse of children by clerics.

Pastoral assistant Ludwig Raischl told the DAPD news agency that the graffiti was removed after police took samples.