Rep. Trey Gowdy, chairman of the House Select Committee on Benghazi, marked his panel's 75th witness interview by announcing "significant breakthroughs" in the investigation of the 2012 terror attack.

"The select committee has made enormous progress this month," Gowdy said Thursday. "We interviewed a top State Department official, Patrick Kennedy, and after months and months of quiet negotiations with the White House, we finally were able to question both Susan Rice and Ben Rhodes."

Kennedy, the State Department's undersecretary for management, reportedly signed off on plans for the temporary diplomatic compound that was raided by Islamic extremists on Sept. 11, 2012 in an attack that claimed four American lives. Kennedy was also the agency's top record-keeping official during Hillary Clinton's tenure, a role that would have given him unique insight into the lapses that allowed Clinton to shield hundreds of Benghazi-related records from investigators by maintaining them on a private server.

The select committee was the first to uncover Clinton's use of a personal server.

Ben Rhodes and Susan Rice were each deeply involved in crafting and publicizing Obama administration talking points in the wake of the attack that blamed the violence on a spontaneous response to an anti-Muslim video clip, a narrative that was later proven completely false.

"In addition, just last week, the committee gained access to crucial national security records we sought for nearly a year – records no other investigation has seen," Gowdy said. "While there are still witnesses to talk to and documents to review, these significant breakthroughs are big wins that will help the committee complete the most comprehensive investigation into what happened before, during and after the Benghazi terrorist attacks, and release a report as soon as possible."

The select committee notched its 75th closed-door witness interview Tuesday with its questioning of Matt Olsen, former director of the National Counterterrorism Center. Olsen was reportedly the first official to characterize the Benghazi raid as a terrorist attack.

Gowdy has said he hopes to wrap up interviews with witnesses in February. His committee will then release a highly-anticipated report on its findings.

For months, the South Carolina Republican has declined to comment on the nature of his investigation's findings despite pressure from congressional Democrats to demonstrate publicly the rationale behind continuing the probe.

A spokesman for Democrats on the committee said Thursday the investigation still has "no end in sight."

"The simple truth is that the facts haven't changed, and the core findings of the many previous investigations have stood up to the repeated and wasteful scrutiny," the spokesman said, arguing the committee's resources have been used as a "tool to target Secretary Clinton."