The sexual harassment scandal surrounding Herman Cain, a leading Republican presidential candidate, deepened as another woman accused him of inappropriate behaviour when he headed a restaurant industry lobbying group in the 1990s.
The woman's account came as Mr Cain tried unsuccessfully to divert attention from the controversy, responding testily to reporters who had pressed him about the original accusations.
The scandal has jolted the contest for the Republican presidential nomination, in which Mr Cain, a former pizza chain executive and political novice, has upended the establishment by climbing to the top of opinion polls.
Mr Cain appeals to some conservatives because he is a political outsider at a time of anti-Washington sentiment that leaves President Barack Obama vulnerable in 2012. So far Mr Cain's backers are sticking with their man.
But the allegations could threaten his standing near the front of the Republican field, which is just two months away from thinning out after early January contests in the traditional lead-off states of Iowa and New Hampshire.
The woman who came forward said he made sexually suggestive remarks or gestures at about the same time that two co-workers at the National Restaurant Association had settled separate harassment complaints against Mr Cain.
She described in conversations with the Associated Press over several days situations in which she said Mr Cain told her that he had confided to colleagues how attractive she was and invited her to his corporate apartment outside work.
She said she did not file a formal complaint against Mr Cain because she began having fewer interactions with him and because her co-workers had already come forward.
Mr Cain's campaign denied he had done anything wrong, decried a "smear campaign" as he is riding high in opinion polls and accused rival Rick Perry's operation of being behind the original stories.
Mr Perry's campaign denied any involvement - and suggested the campaign of yet another candidate, Mitt Romney, might be a source. Mr Romney's campaign said that was not true.