Former Secretary of State Hillary Clinton faced a key moment in her 2016 presidential campaign on Thursday, as she fielded questions from the congressional committee investigating the 2012 attack on the U.S. consulate in Benghazi, Libya, which occurred during her tenure as the nation's top diplomat.

The panel's chairman, Republican Rep. Trey Gowdy of South Carolina, wasted no time on Thursday and attacked Clinton hard in his opening statement, The New York Times reported. The newspaper commented that Gowdy was under pressure to show that the committee's inquiry was not politically motivated.

"Why were there so many requests for security equipment and personnel and why were those requests denied in Washington?" Gowdy asked Clinton. "What did our leaders in Washington do or not do, and when?"

Clinton, for her part, told the lawmakers, investigating the deaths of U.S. Ambassador Christopher Stevens and three other Americans, that the safety of U.S. diplomats had, in fact, been her responsibility, and that she subsequently enacted reform to improve security measures, CNN said. But the former secretary then offered a thinly veiled critique of the committee's work.

"We need leadership at home to match our leadership abroad," she said, "leadership that puts national security ahead of politics and ideology."

Members of the panel also alluded to Clinton's controversial use of a private email server to conduct government business. Indiana Rep. Susan Brooks quizzed her on the lack of messages surrounding two earlier incidents at the U.S. compound in the eastern Libyan city, according to NBC News.

"I did not conduct most of the business that I did on behalf of our country on email," Clinton replied. "I conducted it in meetings, I read massive amounts of memos, a great deal of classified information. I made a lot of secure phone calls, I was in and out of the White house all the time. There were a lot of things happening that I was aware of and that I was reacting to."