(NewsNation) — Elon Musk has come under fire after supporting a tweet that espoused an antisemitic conspiracy theory.

On X, formerly known as Twitter, Musk responded to a user who suggested that Jewish people were espousing hatred of white people and promoting immigration by other groups in an effort to displace whites in the U.S.

“You have said the actual truth,” Musk tweeted.

The original tweet references something known as the great replacement theory, which isn’t exactly new. The roots of the theory go back to the early 1900s, but the conspiracy gained greater traction in 2011 after a book by Renaud Camus told the story of minority groups banding together to take over France.

Modern versions of the conspiracy blame the Jewish people for encouraging immigration by minority groups, which white supremacists claim is an effort to make white people a minority as part of a policy agenda. It also relates to one of the most popular slogans of white supremacist groups, “We must secure the existence of our people and a future for white children.” The phrase is also referenced as 14 words or simply by the number 14 by those who espouse white supremacist beliefs.

The great replacement theory has been linked to violence, with the man who killed 11 worshippers at the Tree of Life Synagogue in Pittsburgh and the man who shot ten people at a supermarket in Buffalo, New York, both referencing the theory in relation to their crimes.

Musk has faced backlash from X users, the Anti-Defamation League and public figures for his comments. Facebook co-founder Dustin Moskovitz called on Musk to resign, not just from X but from all of his companies, which include Tesla and SpaceX. The White House also issued a statement condemning Musk’s words, calling them unacceptable and abhorrent.

“It is unacceptable to repeat the hideous lie behind the most fatal act of Antisemitism in American history at any time, let alone one month after the deadliest day for the Jewish people since the Holocaust. Like President Biden said weeks ago memorializing the victims of the Pittsburgh Synagogue shooting, the October 7 ‘devastating atrocity has brought to the surface painful memories left by millennia of Antisemitism;’ and under his presidency ‘we will continue to condemn Antisemitism at every turn.’ We condemn this abhorrent promotion of Antisemitic and racist hate in the strongest terms, which runs against our core values as Americans. We all have a responsibility to bring people together against hate, and an obligation to speak out against anyone who attacks the dignity of their fellow Americans and compromises the safety of our communities,” the White House said.

Leaders at X also worked to try to contain the damage, with CEO Linda Yaccarino saying discrimination was not acceptable on the platform. Already, the company has seen an impact as IBM pulled advertising on the platform after Musk’s remarks.