WASHINGTON (Reuters) - United States Republican Senator Lindsey Graham on Sunday said he will try to block White House nominations for key jobs until he gets more information on last year's attack on the US mission in Benghazi, even after a TV network pulled back from a story on the attack that Graham had cited.

Sen Graham has threatened to block President Barack Obama's nominations of Ms Janet Yellen to head the Federal Reserve and Mr Jeh Johnson to head the Department of Homeland Security until the administration provides more information on how the attack occurred.

CBS news magazine 60 Minutes on Friday said it would correct an October report on the Sept 11, 2012, assault on the US diplomatic mission in Benghazi, Libya, saying that a source who told the programme that he had been present at the scene gave conflicting testimony to the Federal Bureau of Investigation.

Sen Graham had cited the report - which quoted a security official who described being at the compound during the attack, fighting off an assailant and seeing the ambassador's body - as evidence that the mission did not have adequate security despite indications militants were planning the assault.

Asked on CNN's State of the Union programme if he would lift procedural blocks on White House nominees after the 60 Minutes correction, Sen Graham said: "No. My request has been going on for a year, to talk to the five survivors of the State Department."

Republicans in Congress have said the assault on the mission and the death of Ambassador Christopher Stevens show the Obama administration has failed to maintain security at foreign posts.

Sen Graham is demanding that Congress get to question five State Department employees who survived the attack.

"All I want to do is talk to the survivors, protecting their security, protecting their identity, to find out exactly what did happen," Sen Graham said on CNN.

Several other Republicans also have threatened to put holds on Ms Yellen's nomination, which would require 60 votes from the 100-member chamber to overcome.