Correction: An earlier version of this article failed to mention that Chris Barron, a D.C. resident who made comments critical of Planned Parenthood, had briefly worked for the group and served as board chairman of GOProud, an organization of gay conservatives that has publicly called for Planned Parenthood to lose federal funding. This version includes that information.

Executives of the Susan G. Komen Foundation gave a new explanation Thursday of their decision to cut funding to Planned Parenthood, but their contradictory statements failed to quell a rising controversy that led several of the organization’s affiliates to openly rebel.

Komen had said the decision was the result of newly adopted criteria barring grants to organizations under investigation — affecting Planned Parenthood because of an inquiry by a Republican congressman.

On Thursday, Komen President Elizabeth Thompson told reporters that the funding decision was unrelated to the investigation into whether Planned Parenthood was illegally using federal funds to pay for abortions.

Komen founder Nancy Brinker said the organization wants to support groups that directly provide breast health services, such as mammograms. She noted that Planned Parenthood was providing only mammogram referrals.

The controversy raged across social media, with thousands of messages posted to Komen and Planned Parenthood Facebook pages and advocates on both sides rallying support on Twitter.

Komen’s decision has thrust the foundation, seen for years as a largely apolitical fundraising phenomenon whose pink ribbons and events “for the cure” are among the best-known symbols in public health, into the center of the national debate over abortion.

Brinker said that the decision was not influenced by pressure from anti-abortion groups, as Planned Parenthood has contended, and that others had “mischaracterized” Komen’s new policies. “This has been a contentious issue and one where the essence of our organization’s position has been lost,” she said.

Twenty-six senators — 25 Democrats and one independent — wrote a letter to Brinker on Thursday, urging the foundation to reconsider its decision. One of the signers, Sen. Barbara Boxer (D-Calif.), said the latest justification for defunding Planned Parenthood was tantamount to “revisionist history.”

“This new reason is so obviously fake that you’d have to be born today to believe it,” she said. “They know they have hit a raw nerve with the American people here. They have thrust themselves in the middle of a political witch hunt, aligning themselves with the most right-wing forces . . . and they are hurting because of it. So now they are changing their tune.”

There were also signs of support for the move. Americans United for Life, the anti-abortion group that pushed for the congressional investigation of Planned Parenthood, hailed the Komen decision.

“As a breast cancer survivor, I was always troubled with this whole idea that the nation’s largest abortion provider was enmeshed in the breast cancer fight when they weren’t actually doing mammograms,” said the group’s president, Charmaine Yoest. “I look at this as smart stewardship.”

Meanwhile, Komen executives said donations were up “100 percent,” but executives declined to provide specifics.

Planned Parenthood also reported an outpouring of support, with $650,000 in contributions in 24 hours after the announcement. Of those, $400,000 came from more than 6,000 online donors and $250,000 from the foundation of a Dallas couple. New York City Mayor Michael R. Bloomberg (I) said Thursday that he would donate $1 for every new dollar Planned Parenthood raises, up to $250,000.

The seven Komen affiliates in California issued a statement Thursday saying they were “strongly opposed to Komen National’s new grant-making policy,” which prevents affiliates from funding organizations under investigation at the regional, state or federal level. The California collaborative called the national decision “a misstep.”

Komen’s San Diego affiliate increased its security after receiving threatening e-mails about the new funding policy, even though it does not fund its local Planned Parenthood. Executive director Laura Farmer Sherman said she personally received nearly 400 e-mails on the subject — two in favor of the new policy and 386 against it.

She said she has lost two sponsors for its Race for the Cure next fall.

“The sad thing about this is it’s detracted from what our real mission is, which is the same as Planned Parenthood, which is to save women’s lives,” she said.

The decision has prompted some groups to reconsider or drop their affiliation with Komen, while others are praising Komen for their stance.

A Yale University spokesman said the School of Public Health is reviewing its decision to have Brinker speak at this year’s commencement.

The District-based American Association of University Women, a national women’s advocacy group with 1,000 branches across the country, said Thursday that it would no longer collaborate with Komen. The AAUW said it would not list Komen among the community service opportunities available to the 600 college women expected to attend the AAUW’s annual leadership conference in June. The headquarters office will also no longer sponsor Washington teams in the Race for the Cure and expects its branches to follow suit, said Lisa Maatz, the AAUW’s director of public policy and government relations.

“This whole thing is quite regrettable, and we would really like to see a different outcome,” Maatz said.

Komen board member John Raffaelli said the board voted unanimously in October to change its grant-making criteria, including adding a rule that bans grants to organizations under investigation. During that discussion, Thompson “forewarned us that it would mean Planned Parenthood would get hit by this,” Raffaelli said.

A former Komen public health official, Mollie Williams, who allegedly resigned in protest after the board decision, declined to elaborate Thursday because she said she had to honor the confidentiality of her former employer. In a statement, she said she has spent her career fighting for the rights of the marginalized and underserved. “I believe it would be a mistake for any organization to bow to political pressure and compromise its mission.”

Komen had initially funded 19 Planned Parenthood affiliates but, because of the new funding policies, will continue funding only three of those.

“It was nothing they were doing wrong,” Brinker said of Planned Parenthood. “We have decided not to fund, wherever possible, pass-through grants. We were giving them money; they were sending women out for mammograms. What we would like to have are clinics where we can directly fund mammograms.”

The three that will continue to receive funds are in northern Colorado, Southern California and Waco, Tex., because “they are the only provider” of breast health services in the areas they serve, Brinker said.

Last year, Komen gave Planned Parenthood grants totaling $680,000.

In the past year, Americans United for Life has aggressively pushed Congress to end Planned Parenthood’s federal funding. It has also drafted model legislation that states can use to bar abortion providers from receiving federal funds. Nine states have passed such laws, although the Obama administration has blocked their implementation.

Yoest says the anti-abortion community is exploring ways to support Komen. For the first time, her group will have a team, called “Team Life,” in the D.C. Race for the Cure.

For some Washington residents who contributed to the D.C. Race for the Cure, one of the largest in the country, the decision by Komen is welcome.

Chris Barron, 38, of the District has participated in the Komen race in the city since 2002. He has briefly worked for Planned Parenthood and served as board chairman of GOProud, an organization of gay conservatives that has publicly called for Planned Parenthood to lose federal funding.

For years, Barron said, friends in his conservative circle have been concerned about donating to Komen because of the group’s affiliation with Planned Parenthood. But many of them set aside their political views to contribute.

“Now, the left is unwilling to do the same thing,” he said, calling it “disheartening.”

“This is not the place for them to wage a political fight over abortion. . . . Quite honestly, I can’t believe there aren’t more people outraged at the way Planned Parenthood is behaving.”

Staff researcher Lucy Shackelford and writer Theresa Vargas contributed to this report.