A day after Donald Trump's inauguration as US president, the mood was jubilant at a small Berlin campaign event of the far-right Alternative for Germany (AfD) party, despite the biting winter cold.

"Donald Trump... has of course given us a bit of a tailwind, and now it's our turn to step up," said Daniel Krueger, an AfD councillor greeting supporters at the door in his flat cap and hunting jacket.

Like Trump, the AfD opposes immigration, denies climate change, rails against gender politics and has declared war on a political establishment and mainstream media it condemns as censorious and "woke".

Ahead of Germany's February 23 elections, it is polling at around 20 percent, a new record for a party that has already shattered a decades-old taboo against the far right in post-war Germany.

After Trump's inauguration ceremony, Alice Weidel, the AfD's top candidate, wrote on X that "all of this would also be possible in Germany — you just have to want it. Choose AfD!"

Trump's comeback has been a huge boost for the party, with co-leader Tino Chrupalla among the guests at the inauguration, following right-wing populist gains in Italy, the Netherlands and Austria.

The AfD has also won global exposure thanks to Trump ally Elon Musk, who posted on his X platform that "only the AfD can save Germany" and this month hosted a lengthy and wide-ranging live chat with Weidel.

Inside the Berlin meeting, around 100 supporters applauded as a video showed highlights from the AfD's latest party congress in the eastern town of Riesa.

"At the moment the mood is really, really good," said AfD Berlin chair Kristin Brinker at the event where a cardboard cut-out of Weidel was standing on the bar.

The AfD is not traditionally strong in Berlin, but Brinker said that lately she had been "approached on the street... with comments like 'Great, keep it up!'"

'Close the borders'

At the recent AfD congress, Weidel vowed that a government containing the AfD would force the "total closing of Germany's borders" as well as "large-scale repatriations".

"Re-mi-gra-tion," she bellowed at an enthusiastic crowd.

She also slammed Germany's green energy push with its "windmills of shame" and called for Germany to leave the European Union.

All other parties have ruled out cooperating with the AfD, sections of which are designated as right-wing extremist by Germany's domestic security service.

But its growing success, especially in the ex-communist east, has been met with alarm in the country that once voted Adolf Hitler into power.

Germany's era of "populist immunity is clearly coming to an end. The far right believes its time has finally arrived," said Michael Broening of think tank the Friedrich Ebert Foundation.

He said that "across Europe, far-right parties have learned to soften their stance at least rhetorically when approaching power".

"But in Germany, the AfD remains entrenched in its ideological wilderness," he said, suggesting its political isolation may be driving its radicalisation, and vice versa.

Formed in 2013 as a eurosceptic fringe party, the AfD quickly shifted focus to protest against a mass influx of migrants under Angela Merkel.

The party entered parliament in 2017 with 13 percent of the vote.

Last September, the AfD became Germany's first far-right party in post-World War II history to win a state election outright, in the eastern region of Thuringia.

Bjoern Hoecke, the state's party leader, has been repeatedly accused of historical revisionism and convicted of using a Nazi slogan at election rallies.

Marianne Kneuer, comparative politics professor at Dresden University of Technology, said the recent support from Musk is "something that the AfD finds incredibly affirming and which it can exploit very well".

The AfD has not always been friends with Musk. When he first announced plans to build a Tesla plant outside Berlin, the AfD voted against it, citing environmental concerns.

But Rainer Galla, an AfD candidate in the district, now says that "if Elon Musk correctly recognises that only the AfD can still turn the tide in Germany and save our country, and then publicly expresses that, then I very much welcome that".