U.S. presidential candidate Elizabeth Warren is coming under scrutiny after resurfaced video from 2008 appears to contradict a claim she is now making on her campaign trail.

The Democratic hopeful, 70, told a town hall audience in Nevada on Wednesday that she lost her job teaching special needs students in the early 1970s because she was 'visibly pregnant'.

'By the end of the first year, I was visibly pregnant, and the principal did what principals did in those days - wish me luck and hire someone else for the job,' she told the crowd in Carson City.

However, a YouTube clip posted in January 2008 shows Warren giving a different explanation as to why she left that school.

In the video, she tells interviewer Harry Kreisler that her undergraduate degree was in speech pathology and audiology, and, as such, she didn't have the necessary educational requirements to continue on at the school.

U.S. presidential candidate Elizabeth Warren is coming under scrutiny after resurfaced video from 2008 appears to contradict a claim she is now making on her campaign trail

According to her Wikipedia page, Warren was teaching at the school on an 'emergency certificate' and was required to return to graduate school to take extra courses in education.

She explains in the clip: 'My first year post-graduation, I worked - it was in a public school system but I worked with the children with disabilities. I did that for a year, and then that summer I actually didn't have the education courses, so I was on an 'emergency certificate'.

'I went back to graduate school and took a couple of courses in education and said, 'I don't think this is going to work out for me,' she continues.

The senator then adds: 'I was pregnant with my first baby, so I had a baby and stayed home for a couple of years, and I was really casting about, thinking, 'What am I going to do?''

She makes no mention of the school's principal remarking on her pregnancy.

A YouTube clip posted in January 2008 shows Warren giving a different explanation as to why she left that school

Warren is pictured with her daughter Amelia in 1971. Warren has recently claimed her 1971 teaching position was not extended because she was pregnant

Several viewers of the 2008 clip have left comments beneath the video wondering why there are now apparent discrepancies between her two stories.

'She needs to explain why she is now saying "principal did what principals do" and they fired her. Beyond her other fabrications, is this really someone we want for president?' one asked.

'Whoops!,' another person stated beneath the video.

The new drama comes just one day after it was revealed that Warren campaign's national organizing director, Richard McDaniel, was fired following an investigation.

On Friday, campaign spokesperson Kristen Orthman said leadership had received multiple complaints over the past two weeks about McDaniel, and hired outside counsel to investigate.

'The campaign determined that his reported conduct was inconsistent with its values and that he could not be a part of the campaign moving forward,' Orthman said in a statement.

Orthman did not give details about the nature of the complaints against McDaniel.

In a statement, McDaniel said: 'I have separated from the campaign and am no longer serving as National Organizing Director.

in a statement, McDaniel (pictured) said: 'I would never intentionally engage in any behavior inconsistent with the campaign or my own values.

'I have tremendous respect for my colleagues despite any disagreements we may have had and believe departing at this time is in the best interest of both parties.

'I would never intentionally engage in any behavior inconsistent with the campaign or my own values.

'If others feel that I have, I understand it is important to listen even when you disagree. I wish the campaign and my colleagues well.'

A source told Politico that there were no reports of sexual assault, but could not give further details due to confidentiality.

Warren's campaign to win the Democratic nomination for the 2020 presidential contest has been gaining ground in recent weeks.

She has been rising in public opinion polls, and earlier on Friday she reported an increase in fundraising between July and September.

Warren, a U.S. senator from Massachusetts, last week edged past former Vice President Joe Biden for the first time in a major national opinion poll.