WASHINGTON—A high-ranking American diplomat delivered an emotional reconstruction Wednesday of the Sept. 11, 2012, attacks on the U.S. consulate in Benghazi, Libya, providing the first detailed public account from an American official who was on the ground in Libya.

The testimony from Gregory Hicks, the No. 2 U.S. official in Libya at the time, before the House Oversight and Government Reform Committee also drew new attention to key questions about the attacks, and how the administration handled the aftermath.

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