Evan McMullin
Screen grab taken from a video of Evan McMullin during The Past, Present, and Future of the Republican Party talkPenn in Washington/ YouTube

A CIA veteran and anti-Trump Republican is to launch a bid for the presidency as an independent candidate, US news outlets reported.

Evan McMullin is expected to announce his intention to stand against Donald Trump and Hillary Clinton today, reportedly with financial backing from donors within the Republican Party.

The news was announced on social media by MCNBC's Joe Scarborough who said 'multiple sources' had informed him McMullin would be announcing his presidential bid today (8 August).

In a series of tweets, Scarborough said: "Multiple sources say an independent conservative candidate will announce his candidacy for president today.

"The candidate revealed by sources has an impressive resume and the backing of key $$ contributors in the Republican Party.

"Though he is connected with Republican politics, sources are saying the potential candidate has never held elective office.

"Multiple sources tell me the candidate is Evan McMullin. Wharton grad, CIA alum, Goldman Sachs, Republican Policy Director, US House."

The news comes after a disappointing fortnight for Trump, in which he fell more than 10 points in the polls and is now behind Clinton in almost every voter sample.

McMullin, who is the Republican Party's chief policy director in the House of Representatives, is part of the party's 'Never Trump' contingent and has vocally opposed Trump's policies on social media.

In a statement to ABC News, former CIA agent McMullin said: "In a year where Americans have lost faith in the candidates of both major parties, it's time for a generation of new leadership to step up.

"It's never too late to do the right thing, and America deserves much better than either Donald Trump or Hillary Clinton can offer us. I humbly offer myself as a leader who can give millions of disaffected Americans a conservative choice for President."

The Utah-born potential candidate has not previously held elected office but is well known within the party and is expected to get backing from key Republicans disillusioned with their party's choice of candidate – although it is not yet clear whether McMullin will receive any public backing from GOP members.

McMullin previously worked in Jordan as a volunteer refugee resettlement officer for the United Nations and moved into the CIA shortly before the 9/11 attacks. He spent eight years in the service before moving into banking and then into politics, working his way up from being an adviser on security issues to policy director in just three years.