Mitt Romney accused Vice President Joe Biden on Friday of contradicting the testimony of the U.S State Department officials on Libya, in an escalation of the Republican presidential challenger’s attacks over the deaths of four Americans there:

"The vice president directly contradicted the sworn testimony of State Department officials. He's doubling down on denial and we need to understand exactly what happened as opposed to have people brush this aside. When the vice president of the United States directly contradicts the sworn testimony of State Department officials American citizens have a right to know just what's going on and we are going to find out."

Two State Department officials gave sworn testimony on Wednesday at a congressional hearing in Washington saying they had repeatedly requested beefed up security for the compound before U.S Ambassador Christopher Stevens and three other Americans were killed in the assault at the site on Sept 11th.