The WhatsApp messaging service has been banned from all U.S. House of Representatives devices, according to a memo sent to all House staff on Monday.

The notice said the “Office of Cybersecurity has deemed WhatsApp a high risk to users.

Citing data security concerns, a memo issued Monday by the Office of the Chief Administrative Officer, the House’s Office of Cybersecurity flagged WhatsApp as a “high risk” app due to the lack of transparency in how it protects user data, absence of stored data encryption, and potential security risks involved with its use.”

Reuters reported that the memo pointed to several issues, including a lack of transparency in how the platform protects user data, the absence of stored data encryption, and broader potential security vulnerabilities.

As a result, lawmakers and staff have been advised to uninstall WhatsApp and switch to alternative messaging platforms deemed safer. These include Microsoft Teams, Amazon’s Wickr, Signal, and Apple’s iMessage and FaceTime.

Reacting to the development, a spokesperson for the company said, “We disagree with this decision in the strongest possible terms,” arguing that WhatsApp offers stronger security features than many of the approved alternatives.

In January, WhatsApp disclosed that Israeli spyware firm Paragon Solutions had targeted several of its users, including journalists and civil society members.

In 2022, TikTok was banned from government devices due to similar concerns about data privacy and national security.

“TikTok is considered ‘high risk due to a number of security issues,” the House’s Chief Administrative Officer (CAO) had said in a message sent to all lawmakers and staff at the time, adding that it must be deleted from all devices managed by the House.