Facebook’s F8 conference Tuesday introduced a slew of new features throughout the company’s platforms, including Instagram’s integration with third-party apps like Spotify and GoPro. But despite all the exciting updates and announcements, there was still a dark cloud that loomed over CEO Mark Zuckerberg: Facebook’s ongoing privacy and fake news scandals.

While investigating Russia’s alleged meddling in the 2016 U.S. election, special counsel Robert Mueller discovered Russia had purchased more than $100,000 worth of Facebook ads. A number of outlets reported Russian actors also utilized the popular platform as a vehicle for fake news favorable to President Donald Trump. Zuckerberg addressed this controversy in an open letter via his personal Facebook page:

The world feels anxious and divided, and Facebook has a lot of work to do -- whether it's protecting our community from abuse and hate, defending against interference by nation states, or making sure that time spent on Facebook is time well spent […] My personal challenge for 2018 is to focus on fixing these important issues. We won't prevent all mistakes or abuse, but we currently make too many errors enforcing our policies and preventing misuse of our tools. If we're successful this year then we'll end 2018 on a much better trajectory.

Well, it seems Zuckerberg’s attempts to fix Facebook’s problems will continue well after the year’s end. In a recent interview with Wired, the billionaire said it could take several years to find a solid solution.

“I think this is about a three-year transition to really build up the teams, because you can't just hire 30,000 people overnight to go do something,” he said. “You have to make sure that they're executing well and bring in the leadership and train them. And building up AI tools—that's not something that you could just snap your fingers on either.”

He continued: “The good news is that we started it pretty early last year. So we're about a year in. I think by the end of this year we'll have turned the corner on a lot of it. We'll never be fully done. But I do really think that this represents a pretty major shift in the overall business model and operating model of the company.”

Concerns about Facebook’s security were reignited back in March, after it was revealed Cambridge Analytica—a British consulting firm with ties to Trump—had obtained private information from more than 50 million Facebook users. The scandal prompted Zuckerberg and his team to implement a new feature that, according to Wired, will allow users to clear out all the information the website has gathered on them based on activity.

“Zuckerberg compares this to cleaning the cookies out of one's browser, a form of digital hygiene that he occasionally practices himself,” Wired’s Steven Levy wrote.

But despite his efforts, Zuckerberg is far from off the hook.

A few weeks ago, the tech mogul endured a 10-hour congressional meeting in which he was questioned about the various Facebook controversies, including opioid sales, Russian meddling, and user privacy; however, he has declined the British government’s request to answer their questions pertaining to the Cambridge Analytica scandal, which is why U.K. officials have issued an ultimatum: Zuckerberg can either appear before the Parliament voluntarily, or he’ll be forced to do so the next time he’s in the country.

“We hope that he will respond positively to our request,” UK’s Digital, Culture, Media and Sport Committee wrote in an open letter Tuesday, “but if not [we] will resolve to issue a formal summons for him to appear when he is next in the UK.”