When OpenAI’s advanced artificial intelligence models breached AI startup Hugging Face’s internal systems last week, they carried out a hack in a matter of hours that would have taken a skilled hacker far longer, according to people familiar with the matter.

Typically, a human would need a couple of weeks to complete an attack like this, said the people, who asked not to be named in order to discuss details that have not been publicly released.

OpenAI has been in contact with the U.S. government since learning the breach occurred, one of the people added.