The researchers tied to the NYU Ad Observatory had asked people to download a browser extension that gathered data on what political ads users saw on Facebook - and how those ads were targeted.
But Facebook says that's scraping data in violation of its terms of service. It's disabled the researchers' personal accounts, taken down other apps and Pages tied to the project, and cut off their access to Facebook's APIs (application programming interfaces, technology used to help Facebook interact with other apps or services).
The move follows years of controversy over political ads on the platform, which it doesn't allow to be fact-checked.
“Facebook is silencing us because our work often calls attention to problems on its platform,” researcher Laura Edelson tells Bloomberg.
Facebook shares are 2.6% higher, one of the tech outliers today against a broader market that's lower. The Dow is down 0.8% and S&P 500 down 0.2%, while Nasdaq is up 0.3%.