House Oversight Committee Chairman Darrell Issa, R-Calif., said the hearing will "expose new facts and details that the Obama administration has tried to suppress."
Two members of Issa's staff confirmed hearing witnesses will include federal employees with direct knowledge of the Sept. 11, 2012, attack in Benghazi that killed U.S. Ambassador to Libya Christopher Stevens and three other American citizens, The Hill reported Wednesday.
Rep. Trey Gowdy, R-S.C., a member of the committee, told Fox News Tuesday, "I am not at liberty to disclose the identity of the witnesses, but I will just say it is going to be a very informational and instructive hearing."
At least four State Department and CIA employees are reported to have sought legal counsel so they may speak without fear of retribution, The Hill said, noting the State Department has denied knowledge of potential whistle-blowers and says it protects its employees' rights.
Secretary of State John Kerry accused critics Tuesday of spreading "an enormous amount of misinformation" about the 2012 attack.
At a White House news conference Tuesday, President Barack Obama said he was "not familiar with this notion that anybody has been blocked from testifying" and promised to "find out exactly what [a question on the matter was] referring to."
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