Republican presidential candidate Herman Cain angrily denounced sexual harassment allegations against him on Tuesday and vowed they would not push him out of the 2012 race.

Ain't going to happen, Cain told a news conference, referring to the chances of him giving up his presidential bid.

He described one of the accusers, Sharon Bialek, as a troubled woman produced by the Democrat machine to undermine his candidacy.

Cain said he had never seen Bialek before she held a news conference on Monday to lay out accusations that he made a crude sexual advance towards her when he was head of the National Restaurant Association in 1997.

(Reporting by Steve Holland and Alistair Bell)