Enlarge / Shortly after the FBI posted a notice saying it had seized the dark-web site of AlphV, the ransomware group posted this notice claiming otherwise.

The FBI spent much of Tuesday locked in an online tug-of-war with one of the Internet’s most aggressive ransomware groups after taking control of infrastructure the group has used to generate more than $300 million in illicit payments to date.

Early Tuesday morning, the dark-web site belonging to AlphV, a ransomware group that also goes by the name BlackCat, suddenly started displaying a banner that said it had been seized by the FBI as part of a coordinated law enforcement action. Gone was all the content AlphV had posted to the site previously.

Around the same time, the Justice Department said it had disrupted AlphV’s operations by releasing a software tool that would allow roughly 500 AlphV victims to restore their systems and data. In all, Justice Department officials said, AlphV had extorted roughly $300 million from 1,000 victims.