Story highlights The President claims without providing evidence that 3 to 5 million people voted illegally

Brooks said over the course of the past election there has been "unrelenting voter suppression"

Washington (CNN) The head of the NAACP warned Thursday that his group will "resist" if President Donald Trump goes forward with his "major investigation" into voter fraud.

The President claims without providing evidence that 3 to 5 million people voted illegally in the 2016 US election, although this belief has been widely debunked.

"The President has claimed millions of fraudulent ballots were cast. The only place you will find millions of fraudulent ballots are right beside that fake birth certificate for Barack Obama, inside the imagination of President Trump. They don't exist," Cornell William Brooks, president and CEO of the NAACP, told CNN's Wolf Blitzer on "The Situation Room."

Brooks said over the course of the past election there has been "unrelenting voter suppression."

"We have seen our rights denied as Americans. Particularly seniors, African-Americans, Latinos and younger people," Brooks said. "So, if the President insists upon conducting an investigation into voter fraud as a pretext for voter suppression, the NAACP, along with millions of Americans of every human heritage, will resist. We will push back."

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