Facebook isn’t the same company today that it was during the 2016 presidential campaign, when its platform was used by foreign agents to manipulate American voters, but its chief operating officer says it still has work to do.

The Menlo Park, Calif.-based social media giant now has 30,000 employees devoted to platform security, three times more than in 2017, Sheryl Sandberg said at a Digital Life Design conference in Munich, Germany. It’s also investing in new technology that can flag inauthentic posts like those used by the Kremlin-linked Internet Research Agency to inflame voters before Donald Trump’s unexpected defeat of Democratic rival Hillary Clinton.