WASHINGTON – Be careful out there, especially if you own an Apple mobile device.

The U.S. Marshals Service is warning iPhone and iPad users not to be taken in by ransomware threatening prosecution for child pornography possession if the user doesn’t bribe the force.

According to an alert from the service, the hostage-taking malware infests mobile devices when users visit porn sites. The pop-up invader takes control of the phone or tablet and populates the screen with a message allegedly from America’s oldest federal law enforcement agency. Users are instructed to pay a fee to avoid prosecution and regain control of their device.

“Do not pay the requested fee,” the alert states. “The U.S. Marshals Service does not conduct such activity.”

The marshals urge victims to report the scam to their local phone carrier and/or the FBI. More information about scams, fraud and online safety may be found on the FBI’s website.

Apple’s website offers instructions for removing the malware.