Sen. Lindsey Graham (R-S.C.) said he would put a hold on all Obama Administration nominations pending in the Senate until Congress is given access to survivors of the Sept. 11, 2012 attack on the U.S. Consulate in Benghazi, Libya, that killed Ambassador Chris Stevens and three others. (Chip Somodevilla/Getty Images)

A Republican senator said Sunday that he won’t back down from blocking President Obama’s nominees for Federal Reserve chairman and homeland security secretary in a long-running dispute over the deadly attack on a U.S. diplomatic mission in Libya.

South Carolina Sen. Lindsey O. Graham said nothing had changed even after CBS News admitted Friday that it was wrong to trust a “60 Minutes” source, a former contractor at a British security company, who claimed to be at the scene of the Benghazi assault.

A day after the CBS report aired Oct. 27, Graham announced that he would stall the nominees until the administration allowed attack survivors to talk to lawmakers.

Graham told CNN’s “State of the Union” that he hopes there’s a way to arrange interviews with five State Department employees so he can let the nominations move forward.

“I want to perform oversight,” he said. “I’m not trying to prosecute a crime. I’m not trying to defend the British contractor.”

Graham said he didn’t want to delay nominees Janet L. Yellen at the Fed and Jeh Johnson at the Department of Homeland Security.

“All I want to do is talk to the survivors, protecting their security, protecting their identity, to find out exactly what did happen,” he said. “Was it a protest? Was it an al-Qaeda-inspired attack?”

The raid on Sept. 11, 2012, killed U.S. Ambassador Chris Stevens and three other Americans.

Conservatives contend that the Obama administration tried to mislead the American people in the heat of a presidential campaign by playing down a terrorist attack on Obama’s watch. Republicans have accused the administration of stonewalling their investigations.

The State Department has told Graham that it was concerned about congressional interviews with the survivors of the attack because of Justice Department advice that the survivors could be witnesses in a criminal trial and that any interviews outside the criminal justice process could jeopardize a case.