US Republican Herman Cain suspends campaign

US presidential hopeful Herman Cain has said he is suspending his campaign for the Republican nomination.

He blamed political and media pressure on his family in the wake of "false" allegations of sexual harassment and a 13-year-long extra-marital affair.

"I am not going to be silenced and I'm not going away," he told supporters in his home city of Atlanta, Georgia.

Next month, voters in Iowa will begin the process of choosing a Republican presidential candidate for 2012.

Mr Cain said the allegations against him had taken a toll on his family, but added: "I am at peace."

"I am suspending my presidential campaign because of the continued distraction, the continued hurt caused on me and my family," he told supporters at what had been billed as the opening of his campaign headquarters.

"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.

He said he would endorse another candidate at a later date but gave no hint of where he would direct his supporters to go.

Tweets of praise

On Friday Mr Cain discussed with his wife, Gloria, whether to press on with his campaign.

Last week, an Atlanta woman, Ginger White, 46, came forward to claim she had a 13-year affair with Mr Cain.

Speaking to MSNBC on Thursday, Ms White denied they had been in love, saying: "It was a sexual affair - as hard as that is for me to say."

While rejecting any suggestion of an affair with Ms White, Mr Cain has acknowledged helping pay her monthly bills and expenses, and that his wife did not know about the friendship.

The BBC's Marcus George, in Washington DC, says even before the questions arose about Mr Cain's private life, there were doubts about his plans for tax reform and his understanding of foreign affairs.

The former pizza executive went from obscure longshot to unlikely frontrunner to tabloid fodder.

While Mr Cain's ratings slumped, support for former House of Representatives Speaker Newt Gingrich has surged.

Mr Gingrich has now overtaken frontrunner Mitt Romney in some opinion polls on who should be the Republican candidate to challenge Barack Obama for the White House in November 2012.

Within minutes of his speech, rival Republican candidates - including Michele Bachmann and Mr Gingrich - had tweeted their praise for Mr Cain.

"Herman Cain provided an important voice. His ideas & energy generated tremendous enthusiasm for the conservative movement," Michele Bachmann tweeted.

Mr Gingrich's tweet said: "I am proud to know Herman Cain and consider him a friend and I know he will continue to be a powerful voice for years to come."

Tea Party

Mr Cain made his announcement before the series of state-by-state contests, known as primaries and caucuses, begins next month in Iowa to to choose the Republican nominee.

The former Godfather's Pizza chief executive - who has never won an election - was propelled by conservative Tea Party support to the front of the Republican field in October.

Portraying himself as a business-savvy, anti-establishment outsider, he captured the spotlight with his folksy charm and catchy 9-9-9 tax reform proposal.

But supporters were also alarmed when he made confusing comments about abortion and badly fumbled a question on Libya policy in a recorded interview.