BERLIN (AP) -- The German government has banned the largest "Reich citizen" group, an extremist far-right organization that calls itself the "Kingdom of Germany" and seeks to undermine the country's democratic order, and arrested four of its leaders.

Since early Tuesday, 800 police officers in several states have been searching the association's properties and the homes of leading members.

"The members of this association have created a "counter-state" in our country and built up economic criminal structures," Interior Minister Alexander Dobrindt said, adding that the members of the group underpinned their supposed claim to power with antisemitic conspiracy narratives -- a behavior that the country can't tolerate.

"We will take decisive action against those who attack our free democratic basic order," Dobrindt added.

The so-called Reich citizen, or Reichsbürger, movement doesn't recognize Germany as a state. Many of them claim that the historical German Reich still exists and ignore the country's democratic and constitutional structures such as parliament, laws or courts. They also refuse to pay taxes, social security contributions or fines.

The "Kingdom of Germany" was proclaimed by its leader Peter Fitzek -- who was among those arrested on Tuesday -- in the eastern town of Wittenberg in 2012 and says it has around 6,000 followers, though the interior ministry said that the group has about 1,000 members. It claims to be a "counter-state" that seceded from the German federal government.

"This is not about harmless nostalgics, as the title of the association might suggest, but about criminal structures, criminal networks," the minister told reporters later in Berlin. "That's why it's being banned today."

The group's online platforms will be blocked and its assets will be confiscated to ensure that no further financial resources can be used for extremist purposes.

It's not the first time that Germany has acted against the "Reichsbürger" movement.

In 2023, German police officers searched the homes of about 20 people in connection with investigations into the far-right Reich Citizens scene, whose adherents had similarities to followers of the QAnon movement in the United States.

Last year, the alleged leaders of a suspected far-right plot to topple Germany's government went on trial on Tuesday, opening proceedings in a case that shocked the country in late 2022.