Apple has another ally in its fight against the FBI: Facebook CEO Mark Zuckerberg.

The social network issued a statement of support late last week, but Zuckerberg, one of the world’s most prominent voices on tech policy and privacy, hadn’t said anything personally. Until Monday, that is, when he spoke at Mobile World Congress in Barcelona, Spain, and said that adding back-door access to encrypted devices and messages was not “effective,” nor was it the “right thing to do.”

“We’re sympathetic with Apple on this one. We believe in encryption,” he said. “I expect it’s not the right thing to try to block that from the mainstream products people want to use. And I think it’s not going to be the right regulatory or economic policy to put in place.”

Apple, of course, is in the midst of a legal battle with the FBI, which is demanding that the company create a back door that would allow the government to access private information on an iPhone that was used by killers in the San Bernardino, Calif., massacre late last year. Apple argues that providing that kind of access is a dangerous precedent when it comes to an individual’s digital privacy.

Zuckerberg walked a fine line on Monday, first arguing for encryption but then adding that Facebook also helps the government fight terrorism where it can.

“We feel like we have a pretty big responsibility,” he added. “We certainly do have very strong policies on this that if there’s any content that’s promoting terrorism or sympathizing with ISIS or anything like that, we’ll … get those people off the service. We don’t want people that are doing that stuff on Facebook.”

Zuckerberg should be sympathetic. His own messaging app, WhatsApp, is also end-to-end encrypted, which means Facebook also deals with these security issues. (Facebook doesn’t own the hardware used to send these messages, which is what’s troubling Apple at the moment.)

Encryption was just one part of Zuckerberg’s conversation, though. Here’s what else he had to say.

On Facebook’s strategic and aggressive dive into video: “We hope to not get it wrong twice before getting it right,” Zuckerberg said, a nod to his company’s late and somewhat painful plan to bring Facebook from desktop to mobile four years ago. “Most of the content ten years ago was text, and then photos, and now it’s quickly becoming videos. I just think that we’re going to be in a world a few years from now where the vast majority of the content that people consume online will be video.”

On artificial intelligence, which he described as an advanced form of “pattern recognition”: “One of the most amazing examples I heard recently was having an AI which can now detect skin cancer,” he said. “Pretty soon we’re going to have this tool, that any doctor in the world can deploy, which can basically take a picture of something they think might be a little tumor, and know with the quality and accuracy of the best doctors in the world today whether that’s cancer. This stuff is awesome, but it’s all just pattern recognition.”

On why he likes Facebook live video, the company’s Periscope-like livestreaming video product: “There’s this increasing pressure to do well [on social media],” he said. “In 2016, if you’re sharing a photo you want it to be a good photo. What is really powerful about messaging platforms … and live video now, too, is it gives people more intimate environments and more raw environments where you have a reason to just be yourself. It doesn’t need to feel like it’s super curated.”

On how much screen time he’ll (eventually) allow for his now-three-month-old daughter: “I actually have not yet worked out with [my wife] Priscilla what our policy is going to be on this. But Facebook has a pretty clear policy that you’re not supposed to use it until you’re 13. I wouldn’t be a very good role model if I broke that policy now, would I? For Oculus, which I think is a pretty different thing, that might be under 13, but not for quite a while would be my guess. We’re pretty pro-technology.”