Victoria Toensing, a former Justice Department official and one-time Republican counsel to the Senate Intelligence Committee, told Fox News earlier this week that a State Department employee she represented was threatened by superiors if he cooperated with the House Oversight Committee’s investigation into Benghazi. 

Toensing also suggested that the State Department had refused to provide a process for her to receive classified information to prepare the employee for testimony.

Carney said officials at the Pentagon and State Department were unaware of any requests for an attorney to be granted security clearance.

"Both the State Department and Department of Defense have made clear that they are not aware of any requests for a security clearance for a private attorney," Carney said.

Earlier this week, the State Department denied that employees were being intimidated if they provided new information about the attacks to Congress.

“The State Department is deeply committed to meeting its obligation to protect employees, and the State Department would never tolerate — tolerate or sanction — retaliation against whistle-blowers on any issue, including this one,” spokesman Patrick Ventrell told reporters at a briefing on Tuesday. “That’s an obligation we take very seriously — full stop.”

House Oversight Committee Chairman Darrell Issa (R-Calif.) said in a letter to Secretary of State John KerryJohn Forbes KerryFor the sake of national security, Trump must honor the Iran deal Bernie Sanders’s 1960s worldview makes bad foreign policy DiCaprio: History will ‘vilify’ Trump for not fighting climate change MORE last week the State Department should preemptively provide a process by which attorneys can receive the necessary security clearances.

“It is unavoidable that Department employees identifying themselves as witnesses in the Committee’s investigation will apply for a security clearance to allow their personal attorneys to handle sensitive or classified material,” Issa wrote. “The Department’s unwillingness to make the process for clearing an attorney more transparent appears to be an effort to interfere with the rights of employees to furnish information to Congress.”

Issa said Wednesday that the committee would hold a hearing next week to "expose new facts and details that the Obama administration has tried to suppress."

Meanwhile, the FBI on Wednesday released pictures of three individuals who were on the grounds of the U.S. Special Mission when it was attacked.

The White House would not comment on the release of the pictures, but said President Obama remained committed to "bring to justice those responsible for the deaths of Americans in Benghazi."

"That work is not done, and he is very focused on making sure it is accomplished," Carney said.