A woman who stumbled on evidence of child abuse while looking for information about babies on the Internet helped Spanish police break a child pornography ring.

Police made 13 arrests in different parts of Spain after detecting thousands of images of child pornography following the woman's tip-off, the interior ministry said. The woman called police after she found files with names suggesting paedophilia on an Internet file-sharing site.

Investigators discovered the files contained images of two adults sexually abusing a child.