U.S. Sen. Michael Bennet joined 14 other members of the Democratic caucus on Monday in asking Facebook to crack down on anti-Muslim content and material that violates the website’s policy against calling for individuals to bring weapons to advertised events.

“Of particular concern is how Facebook has addressed the targeting of mosques and Muslim community events by armed protesters through the platform. In June 2019, Facebook responded ??to concerns about these practices by creating a ‘call to arms’ policy,” wrote the senators to CEO Mark Zuckerberg. “Yet, in August 2019, when advocates reported to Facebook that a militia group was using an event page to plan an armed protest at the largest Muslim community convention in the country for the second year in a row, it took Facebook more than a full day to remove the content.”

The lawmakers requested to know whether Facebook intended to develop a plan to implement the call to arms policy through a review of event pages, and whether the company would publish data about hate-based content and its sources. Specifically, they asked for a working group to investigate and remove anti-Muslim content.

Previously, the United Nations investigated how social media, Facebook in particular, contributed to genocidal acts against Rohingya Muslims in Myanmar. One expert said that “Everything is done through Facebook in Myanmar,” including the inciting of violence.

“We believe Facebook must frankly and openly detail the scope of the problem and take concerted and sustained actions to address this problem fully,” the senators wrote.