Donald Trump has mocked congresswoman Alexandria Ocasio-Cortez and her plans to address climate change at a Republican party event, dismissing the left-wing Democrat “a young bartender”.

Speaking to the National Republican Congressional Committee on Tuesday night, Mr Trump attacked Ms Ocasio-Cortez’s so-called Green New Deal proposal as “the craziest thing”, and suggested the Democrats were “petrified” of her.

“The Green New Deal, done by a young bartender, 29 years old,” he said, referring to her previous employment. “A young bartender, wonderful young woman.”

The insult followed Ms Ocasio-Cortez’s attack on the White House security clearance process after a whistleblower claimed several individuals had received approval despite disqualifying issues.

The congresswoman said reports suggested “that we are conducting foreign relations with folks with security clearances via WhatsApp”.

Criminals who worked for Trump Show all 5 1 /5 Criminals who worked for Trump Criminals who worked for Trump Michael Cohen Former lawyer for Donald Trump was sentenced to three years in prison on counts involving evading income tax, false disclosure of the hush money paid to Stormy Daniels and another hush money charge Getty Criminals who worked for Trump Paul Manafort Former campaign manager for Trump Manafort was found guilty in February 2018 of five counts of tax fraud, two counts of bank fraud and one count of failure to disclose a foreign bank account. The crimes occurred prior to his appointment in Trump's campaign Getty Criminals who worked for Trump George Papadopoulos Former Trump campaign adviser Papadopoulos pleaded guilty to lying to the FBI in October 2017. He had lied about making contact with a professor who claimed that the Russians had dirt on Hillary Clinton. He was sentenced to 14 days in jail Getty Criminals who worked for Trump Michael Flynn Former White House National Security adviser Michael Flynn pleaded guilty to lying to the FBI in December 2017. He had lied about conversations that he had with the Russian ambassador to the US during Trump's Presidential campaign. He was not given prison time due to his "significant assistance" to the Mueller investigation Getty Criminals who worked for Trump Rick Gates Deputy chairman of Trump's presidential campaign Gates pleaded guilty to lying to the FBI in February 2018 AFP/Getty

She added: “I mean, every day that we go without getting to the bottom of this matter is a day that we are putting hundreds, if not potentially thousands of Americans at risk.

“What is next? Putting nuclear codes in Instagram DMs? This is ridiculous.”

Her remarks were an apparent reference to evidence previously seen by the committee that the president’s son-in-law Jared Kushner used WhatsApp to communicate with Saudi Crown Prince Mohammed bin Salman.

A Democratic-led committee later voted to subpoena Carl Kline, the former White House security clearance chief, over allegations that the Trump administration inappropriately reversed career officials’ decisions to deny security clearances to some of the president’s advisers.

Whistleblower Tricia Newbold said the Trump administration overruled security experts to give questionable clearances to more than two dozen people.

Two sources familiar with the congressional investigation told Reuters that two of the senior officials whose clearances Ms Newbold said were initially denied were Mr Trump’s daughter Ivanka Trump and Mr Kushner.

Trump addresses National Republican Congressional Committee annual fundraiser on 2 April, 2019 (C-SPAN)

Speaking at the Republican fundraiser event on Tuesday evening, Mr Trump did not address Ms Ocasio-Cortez’s security criticisms, but did concede that the Democrats had a potential electoral advantage on one key issue: health care.

“We have to take that away from them,” the president said. “Republicans should not run away from health care,” he added. “You can’t do it. You’re going to get clobbered.”

He also said some of the Democrats’ proposals could prove enticing to votes in the short term. He said free health care sounds very seductive. “Don’t underestimate the power of socialism to get a vote.”