Social media platforms based in the U.S. including Facebook and WhatsApp will be required to share users encrypted messages by British police under a new treaty among the two countries, according to a character familiar with the matter.

The agreement is estimated to be approved by next month and will force social media firms to give information to support investigations into individuals assumed of serious criminal offences including terrorism and paedophilia.

Priti Patel the home secretary in the UK, has earlier warned that Facebook plans to allow users to send end-to-end encrypted messages would benefit criminals including called on social media firms to develop “back doors”, giving intelligence agencies access to their messaging platforms.

The U.K. and the U.S. have agreed not to investigate each other citizens as part of the deal.

The also the U.S. won’t be able to use information collected from British firms in any events carrying the death penalty.