The United States and allies want to stop Facebook’s plan to apply end-to-end encryption across its messaging services, saying it hinders the fight against child abuse and terrorism.

U.S. Attorney General William Barr wants Facebook to give law enforcement a way to read encrypted messages sent by users.

Facebook’s WhatsApp already has end-to-end encryption, meaning that even Facebook cannot read the text of messages. Facebook plans to extend that protection to Messenger and Instagram Direct.

Barr will make the request to Facebook in a letter with counterparts from the U.K. and Australia as well as U.S. Homeland Security Secretary Kevin McAleenan. They are jopintly calling on the company to suspend plans related to developing end-to-end encryption technology across its messaging services.

Facebook said in a statement that it strongly opposes “government efforts to build backdoors,” which it said would undermine privacy and security.