Facebook shut down the personal accounts and investigation of two New York University researchers into misinformation propagated through political ads.

Facebook claims that the researchers broke its terms of service and collected unauthorized data from its vast network. However, academics claim that Facebook is trying to control research that portrays it negatively.

NYU researchers from the Ad Observatory Project have been studying Facebook’s Ad Library for many years. Here, you can search advertisements that run across all of Facebook’s products.

The access was used to “uncover systemic flaws in the Facebook Ad Library, to identify misinformation in political ads, including many sowing distrust in our election system, and to study Facebook’s apparent amplification of partisan misinformation,” said Laura Edelson, the lead researcher behind NYU Cybersecurity for Democracy, in a statement.

Edelson stated that Facebook’s actions against NYU also prevented other journalists and researchers from accessing Facebook data through the project.

Researchers offered Facebook users a plug-in tool to allow them to volunteer their data and show how the social network targets political ads.

Facebook claimed that the browser extension was designed to bypass detection systems and collect user data, creating privacy concerns.

In a blog post late Tuesday, Facebook said it takes “unauthorized data scraping seriously, and when we find instances of scraping we investigate and take action to protect our platform.”

Facebook sent Damon McCoy and Edelson a cease and desist letter in October. However, they didn’t close their accounts until Tuesday after Edelson told the platform that McCoy and she were looking into the spread of disinformation via the platform regarding the attack on the U.S. Capitol on Jan. 6, the researchers stated.

Mike Clark, Facebook’s product management director, stated in the blog that while the company is open to research that holds them accountable, it doesn’t compromise its security or privacy.

He wrote that while the Ad Observatory project is well-intentioned, “the ongoing and continuing violations of protections against Scrapping cannot be ignored and should not be ignored.”

Two Democratic senators voiced concern about Facebook’s decision. Mark Warner, a Virginia senator, said tech platforms should work with and empower independent researchers, but Facebook has instead “seemingly done exactly the opposite.” Amy Klobuchar, a Minnesota Senator, said that Facebook’s decision to block researcher access to political data has caused her concern. “This has demonstrated that the company continues selling millions of dollars worth of political ads without proper disclosures.”

Facebook claims it makes political ads information available through its Ad Library, and also provides “privacy protected data sets” to researchers via other means.