Mark Zuckerberg on Wednesday said Facebook will audit thousands of apps in response to the “breach of trust” created by Cambridge Analytica, the chief executive’s first comments since a crisis over data siphoned by the political marketing firm used by the Trump campaign erupted Friday.

In a post on his personal Facebook page, Zuckerberg said it would investigate thousands of apps that used large amounts of data at the time. He said that Facebook will give users new tools for how their data is being used and shared and would further restrict developers’ access to data to prevent abuse.

“I started Facebook, and at the end of the day I’m responsible for what happens on our platform,” he said. “While this specific issue involving Cambridge Analytica should no longer happen with new apps today, that doesn’t change what happened in the past. We will learn from this experience to secure our platform further and make our community safer for everyone going forward.”

Specifically he said the company would restrict the data that third party developers can access to a name, profile photo, and email address and will require developers to sign a contract before being allowed to ask Facebook users for rights to their posts. The company will post a new feature on the top of every Facebook user’s new feed with a list of the apps they have used and an easy way to revoke the app’s access.

Until now, Facebook’s top executives have been mum on Cambridge Analytica. Zuckerberg’s last Facebook post was from early March, where his sister photographed him baking cookies at home for the Jewish holiday, Purim. Sheryl Sandberg, Facebook’s chief operating officer, posted on Saturday from her child’s school debate.

Facebook suspended Cambridge Analytica on Friday for having obtained data on as many as 50 million users in an unauthorized way. Earlier this week, Facebook said it would audit the firm to determine if it had deleted the data.

But the silence only seemed to attract more attention to Facebook’s woes — especially after neither Zuckerberg nor Sandberg appeared at a company town-hall meeting on Tuesday. News organizations published articles asking when they would speak. A #DeleteFacebook campaign gained even more momentum after Brian Acton, who made millions after Facebook purchased his app WhatsApp in 2014, said he was deleting the social network.

After the Tuesday meeting, employees posted on social media about how demoralized they felt. In an app for anonymously discussing the workplace, Blind, which requires a corporate email address to join, a Facebook employee posted, “Is this how the downfall of Myspace happened?” Another griped, “So phucked now.” A third person wrote, “I just keep thinking about my stock going to zero with all of this.” Others asked for advice about whether they should sell their stock and said they would advise recruits against joining the company.

Behind the scenes, Facebook was in damage control mode. Lobbyists made the rounds on Capitol Hill. Communications executives sent statements to journalists saying workers and executives, including Zuckerberg, were “outraged” about being deceived. (Little was said about Facebook’s own responsibilities except to defend the legality of their actions.)

Meanwhile, on Facebook’s trending news feed, a feature that showcases news stories on right-hand side of the Facebook website, Facebook users began to comment that there were no stories about Cambridge Analytica in the feed until late Tuesday afternoon. (Stories about Uber and Amazon were on the feed for much of the day.) And business case studies about the company’s efforts to assist political campaigns such as Barack Obama and Bernie Sanders, were no longer indexed on the company’s website.