Ben Carson
U.S. Republican presidential candidate Ben Carson attends a 'Building the New Puerto Rico' event in Fajardo, Puerto Rico, November 8, 2015. Carson said he supports Puerto Rico becoming the 51st U.S. state in Fajardo on Sunday.REUTERS/Alvin Baez

Republican presidential candidate Ben Carson has been the centre of media scrutiny as questions arise about significant moments of his life. The embattled former neurosurgeon is now fighting back, claiming his record is under "special scrutiny" because he is a threat to "the secular progressive movement in this country."

Carson appeared on NBC's Meet the Press on 8 November and said he has never seen a candidate experience the vetting he has experienced in recent days. "I'm a very big threat because they can look at the polling data and they can see that I'm the candidate who's most likely to be able to beat Hillary Clinton. They see that," the recent GOP frontrunner said.

The candidate has been under the microscope over the past few days as more questions arise regarding the factual accuracy of the stories he has published in his books or in interviews he has granted. In one book, Carson claimed he was offered a full scholarship to US military academy West Point. That claim was later refuted by an investigation by Politico.

He attempted to do damage control during an interview with CBS News's Face the Nation, claiming he was told he could receive the scholarship and that his words had been misconstrued. "Well, you notice, I said it was offered," Carson told host John Dickerson. "I didn't say I received it." He added that he included the anecdote in his book because he had "tremendous admiration, obviously, for West Point, which is why I, you know, included that story."

Carson's past alleged experience with extreme violence in Boston and issues with anger management have also been questioned. Despite the scrutiny, Carson thanked "biased media" on Twitter for hauling $3.5m in donations in one week.

The Washington outsider has risen steadily in the polls, overtaking frontrunner Donald Trump in a number of polls. Trump managed to maintain his lead over Carson in two recent polls. The 4 November Quinnipiac poll has Trump leading Carson by one point, 24% to 23%, while the FOX News poll has him ahead by three points, 26% to 23%.