Said Jack Wilson, chairman of the Republican Party of Virginia: "Racism has no place in Virginia".
Northam made headlines on Friday after his personal page from a 1984 yearbook surfaced featuring a photo of two men: one wearing Ku Klux Klan robes and a hood, and the other in blackface.
The yearbook images were first published on Friday by the conservative news outlet Big League Politics.
Ralph Northam in a statement said Saturday that while he was not in a racist picture in his 1984 medical yearbook, he had admitted to "darkening his skin" when he participated in a Michael Jackson dance contest.
In an emailed statement, North Carolina Gov. Roy Cooper said the photograph is both reprehensible and deeply disappointing. It's unclear who the people in the picture are, but the rest of the page is filled with pictures of Northam and lists his undergraduate alma mater and other information about him.
Some Democrats have defended Mr Northam, including leader of the Virginia Senate Richard Saslaw, who said the Governor's photo was "in extremely poor taste" but he had built "a career of helping people of all races".
Every group allied with the governor, from Planned Parenthood to the state Democratic party and Democratic leadership in the General Assembly urged Northam to leave office.
The Virginia Legislative Black Caucus issued a statement saying "we feel complete betrayal" and they were still processing the pictures.
"We still have a lot of issues to work on as we move forward", he said.
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Tran has said she "misspoke" during a legislative session about her bill and wished she had more clearly stated that her bill would not allow infanticide in Virginia, as some suggested after an edited clip of her testimony went viral on social media.
Republican state Sen. Bryce Reeves said in a statement that Northam should resign if the reports of the photos are accurate.
Speaking to the Washington Post, Democratic Virginia state senator Louise Lucas said that Northam had called her on Saturday morning to say that he now didn't believe the picture had him in it, with Lucas reportedly responding that "he should have said that yesterday, then". However, they were at a loss to explain how a mix-up might have occurred that would result in the racist image being placed on his page in error, because students were responsible for submitting their own photos.
"I plan to continue to lead", he said.
The Republicans join a growing chorus of elected officials in Virginia and elsewhere calling for Northam's resignation.
However, Northam's released statement on Friday insinuated he was not ready to resign over the photo.
"Governor Northam has lost all moral authority and should resign immediately", former United States vice president Joe Biden, a Democrat weighing a 2020 presidential run, said on Twitter.
Northam is calling Virginia Democrats to try and gain support.
Biden said Fairfax, a Democrat and only the second African-American to win statewide office in Virginia, "is the leader Virginia needs now".
"We are here today because the history of Jim Crow is still alive and living in the Governor Mansion", said community activist Art Burton, who also touched upon Richmond's racist roots as the capitol of the Confederacy during the Civil War.