Atlanta (US): Herman Cain said on Sunday he is suspending his campaign for the Republican nomination for the US presidency, citing the pain caused to his family of allegations sexual misconduct.

"I am suspending my presidential campaign because of the continued distraction, the continued hurt caused on me and my family," he told supporters in Atlanta, Georgia.

Cain said he would endorse another Republican for the party's nomination in the near future, but vowed to continue to speak out in the future despite his decision not to go forward.

The dramatic announcement effectively ends a campaign that took Cain, a former pizza executive who rose from humble origins, to the front ranks of a Republican field despite his lack of political experience.

His decision followed a drumbeat of accusations that erupted early last month when two women came forth to charge that he sexually harassed them while he was president of a trade lobbying group in the 1990s.

The final blow came this week, when Atlanta businesswoman Ginger White disclosed she had had a 13-year extramarital affair with Cain that ended only eight months ago.

Cain has vehemently denied the charges.

"These false and unproved allegations continue to be spinned in the media and in the court of public opinion so as to create a cloud of doubt over me and this campaign and my family," he said.

"That spin hurts. It hurts my wife, it hurts my family, it hurts me and it hurts the American people because you are being denied solutions to our problems."

(Agencies)