Police in 20 countries have taken down a network that distributed images of child sexual abuse entirely generated by artificial intelligence.

The operation – which spanned European countries including the United Kingdom as well as Canada, Australia, New Zealand – is “one of the first cases” involving AI-generated images of child sexual abuse material, Europe’s law enforcement agency Europol, which supported the action, said in a press release.

Danish authorities led an operation, which resulted in 25 arrests, 33 house searches and 173 devices being seized.