Anyone who uses Facebook Messenger on the smartphone has been issued with an urgent warning.
Apple and Android users have been urged to delete the app, after security concerns were raised.
Cyber security experts have spoken out in criticism of the messaging service, which does not come with end-to-end encryption - reports the Daily Record.
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Messaging apps, such as WhatsApp, which have end-to-end encryption ensure only you and the person you're communicating with can read or listen to what is sent.
Facebook has pledged to make end-to-end encryption the default across all of its messaging services, but the company has told users not to expect it on Facebook Messenger or Instagram Direct until at least 2022.
Cyber-security expert Zak Doffman wrote in a Forbes article: "Messenger users reading this should switch their personal chats to WhatsApp (or Signal) and leave Messenger for trivial comms and kids.
"You should certainly not be using it as the default messaging platform if you’re on Android, where switching from the OS default is an option—unlike on iOS."
Facebook Messenger has responded to the claims.
In a brief statement, the tech service told the publication: "We’re building strong safety measures that are designed to prevent harm from happening in the first place and give people controls to respond if it does.
"Working together also gives us more information to identify abusive accounts and allows us to introduce safety features behind the scenes like restricting interactions between adults and minors.”
But tech experts have also backed Messenger over its decision not to encrypt the platform.
Among the positive points to the current system is a protection for children who could be targeted by predators.
