Paul Ingrassia, the nominee of President Donald Trump to lead a key US federal watchdog agency, has dropped out after the emergence of a series of offensive text messages that he allegedly sent.

Ingrassia, 30, said he was withdrawing his name to lead the Office of Special Counsel (OSC) "because unfortunately I do not have enough Republican votes at this time".

Several Republican senators had warned they would vote against Ingrassia after Politico reported earlier this week that he had sent messages to a group chat in which he allegedly described himself as having a "Nazi streak".

A White House official confirmed to BBC News that Ingrassia was no longer Trump's nominee for the role.

As an independent federal agency, the OSC seeks to protect government employees who blow the whistle on prohibited practices.

In a post on X, Ingrassia, a former right-wing podcast host who serves as a White House liaison at the Department of Homeland Security (DHS), said he would "continue to serve President Trump and this administration to Make America Great Again". His post did not refer to the alleged text messages.

The BBC has asked the White House whether Ingrassia will continue in his role at DHS.

The news broke a day after Senate Majority Leader John Thune, the top Republican in the chamber, cast doubt on Ingrassia's chances of swaying enough senators to vote to confirm him.

When asked if the White House should withdraw his nomination, Thune responded: "I hope so."

"He's not going to pass," Thune added.

Florida Republican Rick Scott also told reporters that he would not support Ingrassia.

In alleged messages published on Monday, Ingrassia reportedly denounced the Martin Luther King holiday, saying it should be "tossed into the seventh circle of hell".

According to Politico, Ingrassia's texts - sent to a group of Republican operatives - also denounced other holidays celebrating black Americans, including Black History Month and Juneteenth - the newest federal holiday.

"I do have a Nazi streak in me from time to time," one text allegedly read.

Edward Paltzik, a lawyer for Ingrassia, did not confirm whether the messages were authentic, and suggested they could have been AI-generated.

In a statement to Politico, he wrote: "Even if the texts are authentic, they clearly read as self-deprecating and satirical humour making fun of the fact that liberals outlandishly and routinely call MAGA supporters 'Nazis'."

The Senate's top Democrat, Chuck Schumer, condemned the alleged messages as "foul and disqualifying".

Republicans control the Senate by a 53-47, and have been mostly unwilling to vote down Trump's nominees. Two other high-profile nominees have also been pulled at the last minute amid doubts about their ability to win over senators.