Moore fallout mounting

(NBC) - Additional Republicans have added their voices to the chorus demanding Alabama Senate candidate Roy Moore drop out of the race after he was accused of sexual misconduct.

"If the choice is between a Democrat and Roy Moore, I choose a Democrat," Arizona Senator Jeff Flake said Tuesday.

Senate Majority Leader Mitch McConnell said Moore is "obviously not fit to be in the United States Senate," while House Speaker Paul Ryan agreed, saying, "If he cares about the values and the people he claims to care about, then he should step aside."

On Monday, a fifth woman, Beverly Young Nelson, came forward to accuse Moore of improper sexual advances when she was a teenager.

"Mr. Moore reached over and began groping me...and he said, 'I am the district attorney of Ettawa County, and if you tell anyone, no one will believe you,'" said Nelson.

Nelson showed where she says Moore signed her yearbook shortly before the incident.

Moore's campaign said the signature is not his and Moore said the allegations are "absolutely false."