The Republican made the remark Saturday at his first public appearance since the allegations were reported by The Washington Post.
Speaking at a Republican club in a Birmingham suburb, Moore questioned why the allegations would emerge now, after he has run five statewide political races in the past 17 years.
Moore called the Post report "fake news" and said the accusations are "completely false and untrue about something that happened nearly 40 years ago." The report said Moore had a sexual encounter with a 14-year-old girl decades ago and had pursued other teenage girls.
Alabama holds a special election on Dec. 12 to fill the U.S. Senate seat previously held by Attorney General Jeff Sessions. Moore is opposed by Democrat Doug Jones.
Moore already denied the allegations in an interview Friday with conservative radio host Sean Hannity.
Longtime Republican political operatives are fearful that the GOP might lose one of its Senate seats in Alabama in spite of Roy Moore's denials that he had a sexual encounter with a 14-year-old girl several decades ago.
The Senate GOP's campaign arm formally ended its fundraising agreement with Moore just a month before the Dec. 12 special election.
The party's presidential nominee in 2012, Mitt Romney, called for Moore to drop out of the race. And two Republican senators, Utah's Mike Lee and Montana's Steve Daines, withdrew their endorsements.
Other Republicans officials have called for Moore to leave the race if the allegations are true. But Moore continues to say they are not true, though he did not rule out dating teenage girls when he was in his early 30s.
This story rewrites 1st sentence to correct Moore quote regarding impending 'revelations.' Links AP Photos.
