The far-right Alternative for Germany party in the eastern state of Saxony-Anhalt is taking legal action over its designation by the state's domestic intelligence service as a confirmed right-wing extremist group.
The state-level AfD party in Saxony-Anhalt filed a complaint in administrative court, deputy state chairman Hans-Thomas Tillschneider told dpa on Wednesday.
A court spokesman said that legal filings would be exchanged but that it is too early to say when a hearing on the case would be held.
In November, the AfD in Saxony-Anhalt was classified as right-wing extremist, citing numerous anti-Muslim, racist and anti-Semitic statements made by functionaries and elected representatives.
The classification gives the agency greater power to place the party under surveillance, including by deploying informants.
The AfD is the strongest opposition party in Saxony-Anhalt's state parliament, holding 23 out of 97 seats.