The accused ringleader of the deadly 2012 attack on the US consulate in Benghazi, Libya, has been ordered to remain in US custody pending trial.
Prosecutors describe Ahmed Abu Khattala, 43, as the commander of the "extremist militia" that attacked the compound.
He has said he was in Benghazi but that he did not take part in the fight.
US ambassador to Libya Chris Stevens and three other Americans were killed in the 11 September 2012 attack.
Heavily armed attackers
Mr Abu Khattala appeared in a Washington DC court on Wednesday, charged with providing material support and resources to terrorists including himself; killing a person on a federal facility; and damaging property of the US by fire and explosives resulting in death.
If convicted, he faces up to life in prison.
A federal judge granted prosecutors' requests to detain Mr Abu Khattala until he can be tried.
In a court document laying out the case for his continued detention, prosecutors revealed new details about the assault and his alleged role in it.
According to prosecutors, the first wave of attackers assembled outside the gates of the mission about 21:45 local time on 11 September 2012, armed with AK-47-type rifles, handguns and rocket-propelled grenade launchers.
"The attackers stole a mission vehicle, forcibly entered and damaged mission buildings and stole mission property," prosecutors wrote. "During this initial attack, buildings within the mission were set on fire."
Ahmed Abu Khattala
•Native of Benghazi in eastern Libya
•Construction worker by trade
•Spent several years in Col Muammar Gaddafi's notorious Abu Salim prison in Tripoli
•Formed his own small militia during the anti-Gaddafi uprising
•Denies any links to al-Qaeda but has expressed admiration for it
•Also denies any role in the attack on the US embassy in 2012, but eyewitnesses report him being there
•US state department says he is a senior leader in Islamist group Ansar al-Sharia
Stevens and diplomat Sean Smith died in the fire, while the remaining state department workers escaped to a separate US facility nearby. That building soon came under attack, and security officers Tyrone Woods and Glen Doherty were killed by mortar fire.
Prosecutors said Mr Abu Khattala entered the destroyed US mission and "supervised the exploitation of material from the scene" by armed men.
According to US prosecutors, in the days following the attack, Mr Abu Khattala "attempted to obtain various types of equipment, including weapons, to defend himself from feared American retaliation for the attack".
'Hatred of Americans'
The government has argued Mr Abu Khattala should remain incarcerated as he remains an ongoing flight risk and poses a danger to others.
"The defendant has repeatedly expressed his hatred of Americans and his efforts to target American and Western interests," the court document states.
American media have reported Mr Abu Khattala was brought to court in Washington from a US Navy warship where he had been held since his capture on 15 June in Benghazi.
US President Barrack Obama praised the raid which led to the suspect's capture last month.
"When Americans are attacked, no matter how long it takes, we will find those responsible and we will bring them to justice," he said.
But Mr Obama and then-Secretary of State Hillary Clinton have faced fierce criticism for not doing enough to prevent the attack and for the White House's political response to it.
Several Republican congressmen have called for Mr Abu Khattala and other terror suspects to be held at the US detention facility in Guantanamo Bay, Cuba.