Donald Trump’s nominee for a top diplomatic post has been withdrawn from consideration after a growing backlash over his past remarks on race and Jewish people left him without crucial Republican support.

Jeremy Carl, who had been tapped to serve as the assistant secretary of state for international organisations – a role overseeing US policy towards bodies such as the UN – announced on Tuesday that he was stepping aside after failing to secure unanimous backing from Republicans on the Senate foreign relations committee.

In a statement posted on X, Carl thanked Trump and the US secretary of state, Marco Rubio, for their support but acknowledged that it would not be enough to secure confirmation.

“With unanimous opposition from Senate Democrats to my candidacy, we also needed the unanimous support of every GOP [Grand Old Party] senator on the Committee on Foreign Relations,” he wrote. “Unfortunately, at this time this unanimous support was not forthcoming.”

The Senate foreign relations committee normally votes on nominations before sending them to the full Senate. Carl’s prospects had appeared shaky since his confirmation hearing in February, when one Republican member of the panel publicly broke ranks.

John Curtis, a Senator for Utah, who is regarded as one of the more moderate Republicans in the chamber, said afterwards that he could not support the nomination, citing Carl’s record of comments on Israel and Jewish people.

“I find his anti-Israel views and insensitive remarks about the Jewish people unbecoming of the position for which he has been nominated,” Curtis said.

The opposition was particularly damaging because Democrats on the committee were already united against Carl, leaving the White House dependent on unanimous Republican backing to move the nomination forward. The failure marks a rare setback for Trump in a Republican-controlled Senate that has largely approved his appointments.

Carl’s withdrawal was welcomed by the American Jewish World Service (AJWS), a non-profit organisation which had highlighted his record of “racist, antisemitic and homophobic views” and petitioned members of the committee to oppose the nomination.

Rori Kramer, the director of US advocacy for the AJWS, said: “We are thrilled to see that Jeremy Carl will not hold this vital role at the State Department. He represents those who’ve turned their backs on the universal human rights that the US has long championed.

“Those rights still matter – for everyone. Because of this, Jeremy Carl was not fit to serve. We oppose any nominee who champions hate and fails to live up to those ideals.”

During his confirmation hearing, senators pressed Carl over a series of past statements that critics said echoed themes associated with white nationalist ideology. Senators questioned him about comments appearing to endorse the so-called great replacement theory – a widely discredited conspiracy theory claiming that elites are deliberately replacing white populations with immigrants.

When asked whether he believed there was a deliberate effort to replace white Americans, he responded that Democratic immigration policies had “certainly sent signs of that”.

Carl told senators he could not recall making some of the remarks cited during the hearing and said he regretted others. He also acknowledged making comments that minimised the impact of the Holocaust, describing them as “absolutely wrong”.

Further criticism centred on earlier writings and interviews in which Carl argued that Jewish people “often love to play the victim” and suggested that resentment towards Jews could arise because historically they had chosen professions that made them “more oppressive”.

He has also criticised the federal holiday of Juneteenth, which marks the end of slavery in the US, calling it a “race-hustling and white-shaming” event.

Carl is a senior fellow at the Claremont Institute, a conservative thinktank, and previously served as a deputy assistant secretary at the interior department during Trump’s first administration.

He added in a second tweet: “I’ve had multiple Senators from our caucus (and not just “based” ones) reach out to me to let me know how disappointed they were in this result. And several Senators went above and beyond the call of duty in supporting me.

“… But unfortunately, we also have a significant number of problem Senators, and with no help from the Democrats and a narrow majority, we’re unfortunately going to see a lot of disappointments. Our voters need to pay attention in primaries and if you have a good Senator, make sure that Senator is holding his weaker colleagues’ feet to the fire.”