Republican South Carolina Senator Lindsey Graham alleges cover-up on Libya

WASHINGTON (AP) -- A senior Republican senator is alleging the Obama administration deliberately covered-up the details of the attack on a U.S. Consulate in Libya that killed four Americans, including the U.S. ambassador.

South Carolina Sen. Lindsey Graham told CBS' "Sunday Morning" that he believes the administration knew within 24 hours that the Sept. 11 attack in Benghazi was a coordinated militia assault. He says the administration described the attack as a spontaneous protest gone awry so that voters would think al-Qaida had been dismantled by President Barack Obama.

Graham said: "Either they are misleading the American people or are incredibly incompetent."

The White House declined to comment on Graham's allegations. It has said previously that an investigation is under way and officials have spoken to the matter as intelligence became available.