Twitter’s chief information security officer is leaving the company, sources familiar with the matter have told The Verge. Michael Coates, who joined the company in January 2015, is quitting to start his own company, sources said. Coates announced the move internally about three weeks ago, sources said, but had not announced the move externally.

Twitter declined to comment. Coates confirmed the move Wednesday afternoon.

Twitter has been an amazing ride, but as I mentioned internally a few weeks back, my time is coming to an end. I’m confident to leave the program with an amazing security team. What’s next? I’m off to co-found a security startup - hope to share more about what we’re doing soon! — Michael Coates (@_mwc) March 21, 2018

News of Coates’ departure comes on the same day that Michael Zalewski, director of information security engineering at Google, announced his departure from that company after 11 years. (Zalewski was a high-ranking security executive at Google but not its chief security officer; that role belongs to Gerhard Eschelbeck, vice president of security engineering.) not And it comes two days after reports that Alex Stamos, Facebook’s chief security officer, plans to leave the company in August. The departures come at a time when tech companies are under mounting pressure to prevent their platforms from being misused by foreign governments and other bad actors ahead of the 2018 midterm elections.

At Twitter, Coates’ interim replacement is Joseph Camilleri, a senior manager for information security and risk, sources said. Camilleri previously filled in for Coates last year when the latter was on paternity leave.

Update, 8:45 p.m.: This article has been updated to include a tweet from Coates confirming his departure. It has also been updated to reflect that Google’s chief security officer is Gerhard Eschelbeck.