A federal German court on Saturday upheld the expulsion of a prominent regional leader of the far-right Alternative for Germany party.

Andreas Kalbitz had won an emergency injunction against expulsion last month but the federal arbitration court ruled the party had the right to kick him out.

The national leadership of the party, known as AfD, in May voted to void the membership of Kalbitz, its chief in the eastern state of Brandenburg, for failing to disclose his ties to extremist groups.

The party is under pressure to distance itself from extremists in its midst after coming under growing scrutiny from Germany’s domestic intelligence agency. AfD came third in the country’s 2017 national election but has recently lost ground in opinion polls.

Kalbitz has a long history of involvement in groups that promote a revisionist interpretation of Germany’s war-time history and was photographed in 2007 at an event hosted by the HDJ, a neo-Nazi youth movement that has since been banned.

Ahead of the decision in federal court, he vowed to fight it if the decision was not in his favor.

Much of AfD’s branch in Brandenburg has stood behind Kalbitz, one of the leading figures on the party’s right wing. He has remained a member of the party’s caucus in the regional parliament.