Washington DC's Metropolitan Police Department has said its computer network has been breached in a targeted cyber-attack, US media report.
A ransomware group called Babuk is reportedly threatening to release sensitive data on police informants if it is not contacted within three days.
The FBI is investigating the extent of the breach, US media reported, citing the Washington DC police department.
[...] On Monday, Washington DC's police department said in a statement that it was "aware of unauthorised access on our server", AP news agency reported.
"While we determine the full impact and continue to review activity, we have engaged the FBI to fully investigate this matter," the statement added, without providing further details of the reported breach.
It is not clear if attackers managed to lock police out of their systems during the breach.