Donald Trump has staunchly defended his embattled Supreme Court nominee against a new allegation of sexual misconduct, calling the accusations against Judge Brett Kavanaugh “totally political”.

The US president spoke a day after a second allegation emerged against Mr Kavanaugh, a development that further imperilled his nomination to the Supreme Court.

Mr Trump, at the United Nations for his second General Assembly meeting, called the allegations unfair and unsubstantiated, made by accusers who come “out of the woodwork”.

He also questioned the political motivations of the lawyers representing the women, saying “you should look into the lawyers doing the representation”.

On Mr Kavanaugh, Mr Trump stressed: “I am with him all the way.”

The new accusation in a report from The New Yorker came just a few hours after negotiators had reached an agreement to hold an extraordinary public hearing on Thursday for Mr Kavanaugh and Christine Blasey Ford.

Ms Ford accuses Mr Kavanaugh of sexually assaulting her at a party when they were teenagers.

He denies the accusation.

Presidential adviser Kellyanne Conway told CBS that the accusations against Mr Kavanaugh sound like “a vast left-wing conspiracy”, using rhetoric that echoed Hillary Clinton’s 1998 description of allegations that her husband, President Bill Clinton, had had affairs.

Mr Trump is suggesting the timing of the New Yorker article is further evidence of what he has been saying privately for days: that the Democrats and media are conspiring to undermine his pick.

Donald Trump
Donald Trump (Jane Barlow/PA)

The second claim against Mr Kavanaugh dates to the 1983-84 academic year, which was his first at Yale University.

Deborah Ramirez described the alleged incident after being contacted by The New Yorker magazine.

She alleged that Mr Kavanaugh exposed himself at a drunken dormitory party.

In a statement provided by the White House, Mr Kavanaugh said the event “did not happen” and that the allegation was “a smear, plain and simple”.

Senator Dianne Feinstein, the ranking Democrat on the Judiciary Committee, called for the “immediate postponement” of any further action on Mr Kavanaugh’s nomination.

Republicans on the Senate Judiciary Committee said they would investigate Ms Ramirez’s accusation.

Taylor Foy, a judiciary spokesman, complained that Democrats “actively withheld information” from the Republicans.

He said they appear “more interested in a political takedown” than a bipartisan process.

The New Yorker said it contacted Ms Ramirez after learning of a possible incident with Mr Kavanaugh.

It said that the allegation came to the attention of Democratic senators through a civil rights lawyer. The Democrats then began investigating.

Ms Ramirez was reluctant at first to speak publicly “partly because her memories contained gaps because she had been drinking at the time of the alleged incident”, The New Yorker reported.

After “six days of carefully assessing her memories and consulting with her attorney, Ramirez said that she felt confident enough of her recollections” to speak publicly, the report said.

Michael Avenatti, the lawyer representing porn actress Stormy Daniels in her legal fight with Mr Trump, claimed to represent a woman with information about high school-era parties attended by Mr Kavanaugh and urged the Senate to investigate.

Mr Avenatti said he will disclose his client’s identity in the coming days and that she is prepared to give evidence before the committee, as well as provide names of corroborating witnesses.

A White House official publicly questioned the accusations coming from Mr Avenatti’s client, saying that the presence of the high-profile lawyer – who has publicly taken on Mr Trump and is weighing a 2020 Democratic presidential bid – makes the proceedings a “circus”.