Blackcat ransomware site claims it was seized; UK law enforcement denies being behind disruption

WASHINGTON (Reuters) - The website used by the hackers responsible for the breach at UnitedHealth Group has been replaced by a notice claiming it was seized by international law enforcement.

But at least one of the law enforcement agencies allegedly responsible for taking the gang down says it had nothing to do with the operation, raising the possibility that the hackers faked their own takedown.

A message posted to the website of the Blackcat hacking gang early on Tuesday said it had been seized "as part of a coordinated law enforcement action" by U.S. authorities and other law enforcement agencies. Among the logos of non-American agencies involved was that of Europol and Britain's National Crime Agency.

U.S. officials and Europol did not immediately return messages seeking comment, but a National Crime Agency spokesperson told Reuters that "I can confirm any recent disruption to ALPHV infrastructure is not a result of NCA activity."

ALPHV is an alternate name for Blackcat. Repeated messages sent to the hackers over several days have not been returned.

(Reporting by Raphael Satter; editing by Jonathan Oatis)