NEW YORK — ABC News anchor George Stephanopoulos will not moderate a Republican presidential debate next winter, part of the fallout from reports that the network’s top political anchor contributed $75,000 over a three-year period to the Clinton Foundation.

Stephanopoulos voluntarily stepped away from the Feb. 6 debate, ABC News spokeswoman Heather Riley said Thursday. It is one of nine debates sanctioned by the Republican National Committee.

The co-host of “Good Morning America” and host of the Sunday morning public affairs program “This Week” earlier apologized for not disclosing his contributions to his employer and viewers. The three donations of $25,000 each in 2012, 2013 and 2014 were made to the foundation set up by former President Bill Clinton because of the organization’s work on global AIDS prevention and deforestation, Stephanopoulos said.

The network news division said in a statement that “we stand behind him.”

Some Republicans have long harbored suspicions about Stephanopoulos because he worked as a top aide to Clinton during his 1992 presidential campaign and in the White House afterward.

Stephanopoulos joined ABC News in 1997, and Riley said the proof of his objectivity as a reporter “is in his work” over 18 years.

With Clinton’s wife, former Secretary of State Hillary Clinton, running for the Democratic presidential nomination, the issues have been revived for ABC News.