One of the U.S. Republican presidential candidates, Herman Cain, is denying a report about sexual harassment allegations in the 1990s.

The news website Politico.com is reporting that Cain was accused by two women of sexually inappropriate behavior while serving as president of the National Restaurant Association.

The report says the women were given five-figure financial settlements as part of a sealed separation agreement with the company that bars them from speaking about it. Neither of the women was identified in the story

Cain's campaign said the report was not true. Cain's spokesman J.D. Gordon called the report an unsubstantiated personal attack.

Cain spoke Monday at the American Enterprise Institute in Washington where he discussed his “9-9-9” tax reform plan. He is scheduled to make two more appearances in the Washington area including one at the National Press Club where he is likely to address the allegations.

Cain is a businessman who has been leading recent polls of Republican candidates who hope to oppose President Barack Obama in next year's presidential election.