(Jewel Samad/AFP)

Republicans repeated a threat to block Brennan's confirmation if the CIA failed to turn over additional documents about the U.S. response to the terrorist attack on the Benghazi consulate.

The threat was first made by Sen. Lindsey Graham (R-S.C.), who suggested last month that Brennan's approval would depend on the White House's cooperation with Congress on the Benghazi affair.

Sen. Richard Burr (R-N.C.) repeated the warning, telling Brennan "it is absolutely essential that we get those documents before we move forward." Brennan made no explicit promises but said he would do "everything in my ability and my authority to be able to reach an accommodation with this committee."