Atlanta (CNN) -- Republican presidential hopeful Herman Cain told supporters Saturday that he is suspending his presidential campaign, which has become hobbled in recent weeks by allegations of sexual harassment and an Atlanta woman's claim that they carried on a 13-year affair.
While he will still be able to raise and spend campaign funds because he did not officially drop out, Cain's White House bid is effectively over.
Cain said he came to the decision after assessing the impact that the allegations were having on his wife, his family and his supporters.
Cain and his wife, Gloria, held hands as they walked up to the podium where Cain made his remarks in Atlanta. The crowd chanted, "Gloria! Gloria!" before the candidate spoke.
Even as he stepped aside under the weight of the allegations that have dogged him, Cain said that he was at "peace with my God" and "peace with my wife."
He repeatedly called the allegations "false and untrue," and added that "the (media) spin hurts."
"I am not going to be silenced and I will not go away," Cain said, announcing what he called his Plan B: A website, TheCainSolutions.com, through which he will continue to advocate for his platform.
His catchy "9-9-9" economic plan is not going anywhere, he said.
"Your support has been unwavering and undying," Cain told his supporters.
He will endorse another of the Republican presidential hopefuls soon, he said.
Other candidates were quick to react.
"Herman Cain provided an important voice to this process," Minnesota Rep. Michele Bachmann said in a statement. "His ideas and energy generated tremendous enthusiasm for the conservative movement at a time it was so desperately needed to restore confidence in our country."
Fellow Georgian Newt Gingrich said the "9-9-9" plan "got our country talking about the critical issue of how to reform our tax code and he elevated the dialogue of the Republican presidential primary in the process."
Texas Gov. Rick Perry said he knew the Cains made a "difficult decision. He helped invigorate conservative voters and our nation with a discussion of major tax reform."
Former Utah Gov. Jon Huntsman said Cain brought "a unique and valuable voice to the debate over how to reform our country's uncompetitive tax code and turn around the economy. I understand his decision and wish him and his family the best."
Recently, Cain acknowledged that Ginger White's allegations of an affair have led to a drop in campaign contributions, and a Des Moines Register poll showed his support among likely Republican Iowa caucus-goers has fallen to 8%, down from 23% in October. The poll has a sampling error of plus or minus 4.9 points, the newspaper said.
Respondents said they were most concerned that Cain does not understand important issues, but said the allegations against him contribute to their concern, the newspaper said.
This week, White told the news media that she and Cain engaged in an on-and-off affair for more than 13 years. She described the affair as "very casual."
White issued a statement, through her attorney, after Cain's announcement Saturday.
"Ginger White respects Mr. Cain's decision regarding his campaign and indeed would have respected any decision he made," the statement said. "That being said, she is disappointed that he has not apologized for the public statements he has made about her and other women who have spoken out."
In a fund-raising letter Tuesday night, Cain referred to White as "troubled."
Two women -- Sharon Bialek and Karen Kraushaar -- previously accused Cain of sexually harassing them in the 1990s while he was head of the National Restaurant Association. Two other women also have said Cain sexually harassed them while they worked at the association, but they have declined to be identified.
Cain told the Union Leader in New Hampshire that he repeatedly gave White money to help her with "month-to-month bills and expenses." But he denied the relationship was sexual, as White contends. He said the two were friends.
"I send checks to a lot of people; I help a lot of people," Cain told Fox News on Thursday. "That in itself is not proof. So the other allegation in terms of it being a 13-year physical relationship, that is her words against my word."
In the interview, Cain said his wife, knew nothing about White nor his financial support for her until the mother of two came forward last week.
"My wife now knows," he told the newspaper. "My wife and I have talked about it, and I have explained it to her. My wife understands that I'm a soft-hearted, giving person."
Cain's announcement came a month before the Iowa caucuses, the first formal test of the primary season, scheduled for January 3.
New Hampshire Republican officials who supported Cain began to survey their options Saturday, with several state representatives saying their support could go to Gingrich or Ron Paul. Cain's most prominent supporter in the state, former GOP state party chair Jack Kimball, said he would wait to learn who Cain would endorse before making his own decision.
Cain told staffers earlier this week he was reassessing his campaign in the wake of White's allegation of an affair, and he acknowledged to reporters Wednesday that her account had led to a drop in contributions to his campaign.
He said in the Thursday Union Leader interview that his wife's feelings, as well as the reaction from supporters and donors, would be important factors in deciding whether he will stay the race.
Cain told the newspaper he would drop out of the race if his wife asked him to, but quickly added that she wouldn't.
Though Gloria Cain rarely makes public appearances or statements, she told Fox News last month that she believed the sexual harassment allegations were "unfounded."
CNN's Rachel Streitfeld contributed to this report.