Facebook has banned UK far-right group Britain First, saying the organization repeatedly broke the social network’s standards by sharing content “designed to incite animosity and hatred against minority groups.” The official Britain First Facebook page has been taken down, as have the official (but not personal) pages for the group’s leader, Paul Golding, and deputy leader, Jayda Fransen.

In a blog post, Facebook said it had warned the group about its posts to no effect, and that the ban was not a decision it took “lightly.” “We are an open platform for all ideas and political speech goes to the heart of free expression,” said Facebook. “[But] there are times though when legitimate political speech crosses the line and becomes hate speech designed to stir up hatred against groups in our society.”

With only a few thousand members and repeated failures to elect government candidates, Britain First has no direct political influence in the UK. But, like many extremist organizations, it’s been an effective communicator on social media. The group’s main Facebook page had more than 2 million likes, and videos it shared on Twitter were notably retweeted by US President Donald Trump last November. Its main focus is Islamophobia, with the group advocating for “invasions” of British mosques and filming visits to supposed “no go” areas in towns and cities where they harangue locals and hand out leaflets.

These videos may simply be stunts, but the group, along with other far-right UK organizations, have helped inspire violence. In June 2016, a British Labour MP named Jo Cox was stabbed and shot to death by a right-wing terrorist, Thomas Mair, who shouted “Britain first” during the attack and “death to traitors” at a later court appearance. Mair’s connection to Britain First has never been proved, but his rhetoric echoed their message online.

Facebook has been struggling for years now with how to deal with extremist content on its platform, but rarely intervenes in such a direct manner. Still, the ban is more symbolic than it is the beginning of an effective campaign against hate groups. One recent investigation from Wired UK found a whole network of Facebook pages linked to Britain First sharing the same content. At the time of writing these pages are still online.