Huma Abedin, arguably the closest aide to Democratic presidential front-runner Hillary Clinton, testified before a congressional committee on Friday about the former secretary of state's handling of the 2012 attack on the U.S. consulate in Benghazi, Libya, that killed four Americans.

The House select committee, led by Rep. Trey Gowdy, R-S.C., quizzed Abedin behind closed doors, and her testimony was expected to take several hours, the Associated Press reported. Rep. Elijah Cummings, the top Democrat on the panel from Maryland, meanwhile, slammed Gowdy's move to question the aide, arguing that her knowledge of details at the time of the attacks was minimal.

"She had no policy responsibilities, no operational responsibilities and was not with Secretary Clinton on the night of this phenomenal tragedy," Cummings told reporters during a break.

But Rep. Lynn Westmoreland, R-Ga., told CNN that Abedin's testimony had been useful. The Clinton confidant spoke for roughly 30 to 35 minutes and had been "forthcoming" and "very nice," Westmoreland commented.

"If you look at what her job was, you would think she would have some knowledge of some of the events," he said. "I imagine everyone at the State Department had some knowledge."

The Benghazi inquiry and Clinton's use of a private email server to conduct government business have both been headaches to her campaign as the 67-year-old politician seeks the Democratic presidential nomination. In a written statement, her campaign thus questioned the procedures adopted by Gowdy.

"[Abedin] has been nothing but entirely cooperative with the committee's requests. Yet it remains unclear why the committee is focused on her, given her lack of knowledge about the events surrounding Benghazi," Clinton campaign spokesman Nick Merrill wrote.

"The committee's focus on (Abedin) is additional evidence that the actual attack in Benghazi, and its lessons about how we might better protect diplomats serving in dangerous places, are the last things on the committee's mind," he charged.