The Libyan militant charged in the Benghazi attacks has pleaded not guilty to conspiracy.
Ahmed Abu Khattala made his initial appearance in federal court in Washington on June 28.
A grand jury indictment says Abu Khattala took part in a conspiracy to provide material support and resources to terrorists in the 2012 attacks that killed U.S. Ambassador Chris Stevens and three other Americans.
Abu Khattala was flown by a military helicopter from a Navy ship to Washington earlier on June 28.
He was captured in Libya by U.S. special forces two weeks ago.
The September 11, 2012, attack sparked controversy in the United States with Republicans accusing the Obama administration of misrepresenting the circumstances and of lax protection for diplomats.
Initially, the Obama administration claimed that the attack began as a spontaneous protest against the anti-Islam film, Innocence of Muslims.
Later, the White House said the attack was a premeditated assault by Islamic militants.