Correction: An earlier version of this story stated that Judy Woodruff donated $1,000 to the Clinton Foundation in 2010. She donated $250. This version has been updated.

Former White House adviser George Stephanopoulos is chief political correspondent for ABC News and anchor of its election coverage. (Ida Mae Astute/ABC)

ABC News chief anchor George Stephanopoulos made three contributions to the Clinton Foundation, ABC confirmed Thursday, in an apparent conflict with his duties as a journalist.

Stephanopoulos contributed $25,000 in 2012, 2013 and again last year to the charitable organization headed by former president Bill Clinton, Hillary Rodham Clinton and their daughter, Chelsea.

“PBS NewsHour” co-anchor Judy Woodruff also said that she had made a one-time donation to the charity — $250 in 2010.

Sen. Rand Paul (R-Ky.), a presidential candidate, said Thursday that Stephanopoulos’s donations should preclude him from moderating any debates during the 2016 presidential campaign.

Stephanopoulos, ABC’s chief political correspondent, was already regarded warily by Republicans because of his long association with the Clintons. He was a key adviser to Bill Clinton during his campaign in 1992 and served as a senior White House aide during Clinton’s first term. Republicans and media ethicists said the contributions raised questions about his objectivity and neutrality, particularly since he is likely to cover Hillary Clinton’s presidential campaign.

ABC said that Stephanopoulos has decided not to moderate a Republican debate sponsored by the network and the Republican National Committee scheduled for Feb. 6. ABC News spokeswoman Heather Riley declined to say whether his decision was prompted by Paul’s criticism.

Stephanopoulos is the second major news anchor to run into ethical problems during the past three months. In February, NBC News suspended anchor Brian Williams for six months without pay for apparently exaggerating his reporting exploits over the years.

ABC said it has no plans to punish Stephanopoulos, issuing a statement saying that he had made “an honest mistake” and that the network was standing by him.

The network said Thursday morning that Stephanopoulos had made two annual contributions of $25,000 to the Clinton Foundation in 2013 and last year. But he subsequently checked his records and found that his donations began in 2012, the network said.

Stephanopoulos is co-host of “Good Morning America” and moderator of “This Week With George Stephanopoulos,” the Sunday morning public-affairs program. The network said that he would address the contribution issue Friday on “Good Morning America.” He was not made available for an interview.

The charitable contributions, first disclosed by Politico after ABC received inquiries from the Washington Free Beacon, are potentially problematic because journalists are supposed to be independent of the people and organizations they cover.

“Being a journalist doesn’t mean you can’t be a citizen, or that you can’t vote or serve on the PTA. It does mean you can’t be on the PTA if you’re the education reporter,” said Tom Rosenstiel, executive director of the American Press Institute, a research and training organization based in Arlington, Va. “If you have a conflict, people don’t know where your loyalties lie. . . . This should have been a clear, bright line for Stephanopoulos, because he came from the Clinton administration. He should be doubling over backward to demonstrate his independence.”

Stephanopoulos’s contributions to the Clinton charity were not disclosed last month when the ABC host interviewed Peter Schweizer, the author of “Clinton Cash,” a book about the Clintons and their foundation, on “This Week.”

During the interview, Stephanopoulos expressed skepticism about the book’s assertions that Hillary Clinton may have tied her actions as secretary of state to donations from foreign governments. Stephanopoulos said that ABC, other media outlets and independent investigators had not found “a smoking gun” tying her to any policy changes based on donations to the foundation.

In a statement issued Thursday morning by ABC, Stephanopoulos said: “I made charitable donations to the foundation in support of the work they’re doing on global AIDS prevention and deforestation, causes I care about deeply. I thought that my contributions were a matter of public record. However, in hindsight, I should have taken the extra step of personally disclosing my donations to my employer and to the viewers on air during the recent news stories about the foundation. I apologize.”

ABC News also issued a statement: “As George has said, he made charitable donations to the foundation to support a cause he cares about deeply and believed his contributions were a matter of public record. He should have taken the extra step to notify us and our viewers during the recent news reports about the foundation. He’s admitted to an honest mistake and apologized for that omission. We stand behind him.”

Woodruff acknowledged in an interview Thursday that she contributed $250 to the Clinton Foundation in 2010, responding to an appeal from former presidents Clinton and George W. Bush in the wake of the Haitian earthquake.

Woodruff said she thought the donation was appropriate because “there was no political agenda or advocacy involved” in the foundation’s mission. At the time, Hillary Clinton was not a candidate. But in light of Hillary Clinton’s presidential campaign, “I need to be more careful,” she said.

“NewsHour” has also reported on questions surrounding the Clinton Foundation without disclosing Woodruff’s contribution. She said that the news organization will “have to have a conversation about what our policy will be” about disclosing the contribution in future reports.

Public records kept by the Clinton Foundation show that News Corp., the parent of Fox News Channel, and Turner Broadcasting, parent of CNN, have also made donations.

News organizations usually permit charitable contributions by their employees but frown on any association with causes or organizations that their journalists might cover.

NBC News, for example, handed out brief suspensions to MSNBC hosts Keith Olbermann and Joe Scarborough in 2010 for making contributions to political candidates. The network said that the hosts had violated a policy requiring employees to clear such contributions with management.

Fox News in 2010 prohibited host Sean Hannity from broadcasting his program from a rally held by supporters of tea party candidates.