But speaking on the BBC's "Desert Island Discs" radio show Sunday, Sandberg said that the metadata provided by WhatsApp has the potential to inform governments about possible terrorist activity.

"It is completely unacceptable; there should be no place for terrorists to hide. We need to make sure organizations like WhatsApp, and there are plenty of others like that, don't provide a secret place for terrorists to communicate with each other," Rudd told the BBC's Andrew Marr show at the time.

The encryption — a way of protecting information — of WhatsApp messages has been under fire from politicians such as U.K. Home Secretary Amber Rudd. She criticized the app after terrorist Khalid Masood sent a WhatsApp message shortly before launching an attack on London's Westminster Bridge in March.

Facebook's chief operating officer, Sheryl Sandberg , has said that removing the encryption on WhatsApp messages would prevent governments from getting information about how terrorists communicate.

"The goal for governments is to get as much information as possible. And so when there are message services like WhatsApp that are encrypted, the message itself is encrypted but the metadata is not, meaning that you send me a message, we don't know what that message says but we know you contacted me," she said.

"If people move off those encrypted services to go to encrypted services in countries that won't share the metadata, the government actually has less information, not more. And so as technology evolves these are complicated conversations, we are in close communication working through the issues all around the world."

Sandberg recently met Rudd and told "Desert Island Discs" that Facebook and the U.K. government are "very aligned in our goals".

"We want to make sure all of us do our part to stop terrorism and so our Facebook policies are very clear. There's absolutely no place for terrorism, hate, calls for violence of any kind. Our goal is to not just pull it off Facebook but to use artificial intelligence and technology to get it before it's even uploaded.

"We are working in collaboration with the other tech companies now, so if a video by a terrorist is uploaded to any of our platforms, we are able to fingerprint it for all the others so that they can't move from platform to platform."