German Chancellor Angela Merkel has dismissed a minister for praising the election of a liberal candidate who was supported by the far right.
The candidate, Thomas Kemmerich, won an election in the state of Thuringia with the backing of the far-right AfD party.
Christian Hirte, who belongs to Mrs Merkel's CDU party, tweeted his congratulations afterwards.
Mr Kemmerich's victory with AfD support was seen as a political earthquake. Mrs Merkel said it was "unforgiveable".
Wednesday's election broke a taboo in German politics that mainstream parties do not work with the far right, and led to outrage among Ms Merkel's centre-left coalition partners in the national government, the Social Democrats (SPD).
As the vote sent shockwaves through Germany, Mr Hirte tweeted to FDP politician Mr Kemmerich: "Your election as a candidate of the middle shows once again that the Thuringian [left-wing] red-green alliance has been voted out for good."
The tweet was widely condemned, and Sven Kindler, Green Party member of the German parliament - the Bundestag - replied: "Forming pacts with Nazis and also giving your congratulations, what a shame."
Mr Hirte was a minister for former East German states and secretary of state for the economy and energy. In a brief statement, Mrs Merkel's spokesman, Steffen Seibert, said: "The chancellor has today proposed to the federal president the dismissal of Secretary of State Christian Hirte."
In a follow-up tweet sent on Saturday, Mr Hirte confirmed that he had been fired.
"Chancellor Merkel has told me... that I can no longer be the Federal Government Commissioner for the new states," he wrote. "Therefore, following her suggestion, I have asked for my discharge."
What happened in Thuringia?
This was the first time in post-war Germany that a leader has been helped into office by the far right. Mainstream parties officially oppose any deals with the AfD, which has grown to become the main opposition party in the Bundestag.
Faced with a major backlash to his election win, Mr Kemmerich announced on Thursday that he would resign - just 25 hours after he was elected - and called for a snap election.
The following day he said his lawyers had advised him to stay on temporarily, but reversed this on Saturday, announced he was standing down "with immediate effect".
He has said he would turn down a pay package of €93,000 (£79,000; $102,000), which he was legally entitled to under Thuringia law even though he only served one day in office.
More on Germany's AfD
Senior MPs in Thuringia's parliament plan to meet on 18 February to decide on a constitutional way to re-run the election for state premier.
No replacement has been chosen yet for Mr Kemmerich. There are calls for the public to vote in fresh regional elections in Thuringia, but Chancellor Merkel's Christian Democrats (CDU) are resisting that option.
The CDU and the SPD were holding crisis talks on Saturday.