Ransomware doesn’t only target desktop and laptop computers, but some cell phones as well, according to internet security experts.

“We’ve seen Ransomware start to be developed for Android mobile devices,” said Eric Klonowski, Senior Advanced Threat Research Analyst at the anti-virus company Webroot. “All this is a major concern.”

Mobile phone ransomware looks very similar to what you might see on a computer.

Ransomware has not shown up on iPhones yet, Klonowski says.

“It’s highly unlikely that we will see iPhone ransomware sneak through the app store. In addition to reviewing all apps, Apple has a number of security measures in place that prevent apps from interacting with other apps or your pictures, data, etc. while installed,” he said. “Android phones also have similar security measures, but the user can often be coerced to disable it. Successful iPhone ransomware would require a very sophisticated attack on an unprecedented scale.”