Germany's domestic intelligence agency has designated the largest opposition alternative, Für Deutschland (AFD), as a "confirmed right-wing extremism" force, which means authorities can strengthen their surveillance as critics demand that it be legally banned.

The Federal Office for Constitutional Protection (BFV) had previously believed that anti-immigration, pro-Kremlin party "suspected" threats to Germany's democratic order, with three AFDs classified as confirmed extremists in the AFD regional chapters of the eastern states and their youth.

The AFD ranked second in the February general election with more than 20% of the vote, and he said he would challenge BFV's decision in court.

BFV said it has concluded that the racist and anti-Muslim stance proposed by the AFD is “incompatible with the basic order of liberal democracy as stipulated in the country’s constitution” based on the “national-based understanding” of German identity.

It said the party “is aimed at excluding certain demographic groups from equal participation in society in order to allow them to accept unconstitutional unequal treatment, thus allowing them to allocate legally devaluable status”.

The decision will clear the difficult measures to monitor the parties for illegal activities, including tapping telephone communications, observing their meetings and recruiting secret informants.

The AFD is led by Alice Weidel and Tino Chrupalla, who call on them to “immigration” for people who are considered “migrants”, including German citizens who have taken root abroad.

In a joint statement, Weider and Krupara called the BFV's decision "a politically motivated" and "had a severe blow to Germany's federal democracy." "The AFD will continue to defend itself legally against these defamatory remarks that endanger democracy," they said.

Donald Trump's Secretary of State Marco Rubio described the BFV ruling as "a tyranny in disguise." "The real extremists are not the popular AFD - second in recent elections, but the agency's deadly open border immigration policy," Rubio said on social media.

The AFD faces growing calls from opponents to ban it on grounds that it aims to undermine democratic values, including protecting minority rights. The House of Representatives (the federal government or government) can seek such a ban, or it can be sought by the government itself.

The German parliament could use the BFV decision to prove an attempt to cut or block the party's public funding.

But outgoing Social Democratic Prime Minister Olaf Scholz warned not to rush to ban the AFD. Some opponents of the ban say it could backfire and help promote victim narratives within the party.

Next week, Christian Democratic Union leader Friedrich Merz will be sworn in as Germany's new prime minister after his conservative group won a quick election in February. But his party has lost its stance since the vote, with several recent polls showing AFD’s No. 1.

Meles will lead the center-right government with the Social Democrats. Their alliance agreement prohibits any explicit or implicit cooperation with the AFD, a policy that is a key "firewall" that all mainstream political parties call the protection of German democracy.

However, Merz faces calls within his party to view AFP as a normal opposition force to prevent it from imposing itself among political martyrs.

Meles himself faced intense criticism in January as he accepted support for the motion of parliament to limit immigration, which was called "unforgivable mistake" before the election.

The AFD won a record seat in the election, and in theory it has the authority to chair several key parliamentary committees. However, the BFV decision may make other political parties less willing to support such an outcome.

Analysts say the new administration will have a limited window to win voters’ trust or win directly the AFD victory in the next general election scheduled for 2029.

The party, with about 51,000 members, made huge gains from voters’ frustration with immigration policies and the sick economy last year.

It first appeared in the regional elections in Thuringia in September, the first time since the Nazi period that far-right parties won state polls. In the same month, it also performed well in the other two former communist areas.

After Elon Musk's active recognition during the campaign, the U.S. Congressman (AFD) has achieved the best national results since World War II.

Cologne-based BFV is based on a 1,100-page report submitted to the Ministry of the Interior this week.

The report outlines the party’s efforts to erode democracy, including inciting hostility to asylum seekers and immigrants, and German citizens who are considered inferior “in the context of immigration to primarily Muslim countries.”

Political analysts and security authorities say the AFD was established by a group of Eurosceptics 12 years ago and has become more radical with every change in leadership, especially when the country faces a flood of refugees in 2015-16.

Benjamin Winkler of the anti-seniorist Amadeu Antonio Foundation welcomed the BFV’s decision, accusing the AFD of increasing the influence of radical organizations while inspiring racist and anti-immigrant sentiment among the wider population.

"We see this in a large number of reports on the attacks, as well as police data on the number of right-wing extremist crimes in Germany," he told news channel N-TV.

The French also repeatedly called for interruption of the historical memory culture of the Holocaust with Germany and used the thin Nazi slogans that were forbidden in Germany.

In a live chat with Musk in January, Weidel called Adolf Hitler a Communist.