PHOENIX (AP) — Federal law enforcement authorities are in the process of seizing Backpage.com and its affiliated websites.

A notice that appeared Friday afternoon at Backpage.com says the websites are being seized as part of an enforcement action by the FBI, U.S. Postal Inspection Service and the Internal Revenue Service.

The notice doesn’t characterize or provide any details on the nature of the enforcement action.

It says authorities plan to release information about the enforcement action later Friday.

Backpage.com lets users create posts to sell items, seek a roommate, participate in forums, list upcoming events or post job openings.

But Backpage.com also has listings for adult escorts and other sexual services, and authorities say advertising related to those services has been extremely lucrative.