As of this week, Twitter has made sure that federally funded fusion centers can no longer use a powerful social media monitoring tool to spy on users.

The move comes after the ACLU informed the company that Dataminr (a firm that creates Twitter surveillance tools that can visualize and track trends on the platform) was providing its services to the federally funded hubs.

“Using Dataminr, fusion centers like JRIC could search billions of real-time and historical publictweets and then potentially share information with the federal government,” Nicole Ozer, the technology and civil liberties policy director at the ACLU of California, wrote in the blog post.

“These are massive hubs for information collection and monitoring and surveillance of individuals,  The information they collect is often about innocent people.”

By giving government agencies access to these tools, Dataminr was also clearly violating Twitter’s policy prohibiting the use of its data for surveillance, according to the ACLU.

“It’s really even more important now than ever that the companies have strong policies in place and that they have the right auditing and enforcement to make sure those rules are followed,” Ozer said.

In a statement, Dataminr asserted that it had never offered the government access to Twitter’s raw user data, and that the ability to export data was not a feature of the platform. “We offer a limited version of our product, which provides tailored breaking news alerts based on public Tweets, to those supporting the mission of first response,” said Dataminr, while emphasizing that it shared in Twitter’s commitment to the privacy and civil liberties of its users.

“We have worked closely with Twitter to modify our product and incorporate feedback that ensures the strongest safeguards are in place for people who use Twitter,” the company said.

Datamnir’s close relationship with United States law enforcement first came to light in April of this year, when a report by the Intercept claimed the company — along with other developers of social media surveillance tools — had received funds through the CIA’s venture capital firm, In-Q-Tel.

A few months later, in October, Twitter suspended one of those CIA-backed firms’ from accessing its commercial data after the ACLU claimed it was being used by the police to target protesters. In this case, the tool in question was Geofeedia — a social media mapping software that had allegedly been used by law enforcement in Oakland and Baltimore.