The premier of Germany's Thuringia state stepped down and called for snap elections Thursday, barely 24 hours after he was elected with the help of far-right AfD lawmakers in a vote Angela Merkel called "unforgivable".

Thomas Kemmerich, from the liberal Free Democrats (FDP), said he would apply for the regional parliament to be dissolved in response to the outrage over his appointment, which drew comparisons with the rise of the Nazis in the 1930s.

"We want new elections to remove the stain of the AfD's support from the office of the premiership," he told reporters, adding that his resignation was "unavoidable".

Angela Merkel, Chancellor of Germany, called for the election result to be 'reversed'
Angela Merkel, Chancellor of Germany, called for the election result to be 'reversed' AFP / Phill Magakoe

Kemmerich's election on Wednesday marked the first time in German post-war history that a state premier was helped into office by accepting far-right votes, crossing a red line in a nation haunted by its Nazi past.

He became the surprise winner of a run-off vote after AfD lawmakers ditched their own candidate to back him.

Chancellor Merkel called the vote "unforgivable" and said the result "must be reversed".

She reiterated that her centre-right CDU would never work with the anti-Islam, anti-immigrant AfD, on a regional or national level.

Thomas Kemmerich from the liberal Free Democrats (FDP) stunned Germany by winning a run-off vote for the Thuringia premiership, after fari-right AfD lawmakers backed him
Thomas Kemmerich from the liberal Free Democrats (FDP) stunned Germany by winning a run-off vote for the Thuringia premiership, after fari-right AfD lawmakers backed him AFP / JENS SCHLUETER

Thousands took to the streets in cities across Germany late Wednesday to vent their dismay at the vote outcome, including in Berlin, Frankfurt and Thuringia's capital Erfurt.

Some carried signs that read "Never again", while others recalled that it was in Thuringia in 1930 that a Nazi minister was first allowed into government.

Composition of the state parliament of Thuringia in Germany, in seats by party.
Composition of the state parliament of Thuringia in Germany, in seats by party. AFP / Valentina BRESCHI

The aftershocks of the crisis were being felt in Berlin too, since Thuringian state lawmakers from Merkel's own CDU lined up with the FDP and far right in voting for Kemmerich over popular incumbent Bodo Ramelow from the far-left Die Linke.

Merkel's federal coalition partners, the centre-left Social Democrats, reacted furiously to the debacle, calling for her conservative party to clearly distance itself from the AfD.

"There can be no carrying on as usual without resolving this problem," fumed SPD co-leader Norbert Walter-Borjans.

The SPD and CDU are to hold crisis talks in Berlin on Saturday.

Thomas Kemmerich from the liberal Free Democrats (FDP) stunned Germany by winning a run-off vote for the Thuringia premiership, after fari-right AfD lawmakers backed him
Thomas Kemmerich from the liberal Free Democrats (FDP) stunned Germany by winning a run-off vote for the Thuringia premiership, after fari-right AfD lawmakers backed him AFP / JENS SCHLUETER

Addressing the controversy during a visit to South Africa, Merkel called Wednesday's vote "a bad day for democracy" and said the role played by her local allies "broke with the values and convictions of the CDU".

Christian Lindner, national leader of the FDP, one of Germany's smaller parties, announced a vote of confidence on his own leadership on Friday.

If Kemmerich gets the necessary two-thirds majority to dissolve Thuringia's parliament, ousted premier Ramelow told Spiegel weekly he was "ready to throw his hat in the ring again".

According to the latest surveys, Ramelow has a 71 percent approval rating in Thuringia. His Linke party is tipped to come first in fresh polls but fall short of an overall majority.

In states across Germany's former communist east, the AfD is a major political force and mainstream parties are increasingly scrambling to keep it locked out of the corridors of power.

In Thuringia, the AfD is led by Bjoern Hoecke, one of the party's most radical figures who has called for a "180-degree turn" in Germany's atonement for Nazi crimes.

A picture of Hoecke shaking hands with Kemmerich after the election win was splashed across the front pages of German newspapers.

"The handshake of shame", screamed best-selling daily Bild, slamming Kemmerich for "letting himself be elected by a neo-Nazi".

On social media, the picture was quickly twinned with one of Adolf Hitler shaking hands with German president Paul von Hindenburg in 1933, the year Hitler became chancellor.

Since its creation in 2013, the AfD has gone from strength to strength in Germany, capitalising on anger over Merkel's 2015 decision to allow in over a million asylum seekers.

At the last general election, the party scored almost 13 percent nationwide.

The SPD's Walter-Borjans warned that the world was watching how Germany dealt with the rise of the far right and the "breach in the dam" in Thuringia.

"What has happened here is a signal that we can't allow to go unanswered," he said.