The defendant, Abd al-Rahim al-Nashiri, was not present at Wednesday’s secret session. The judge, Army Col. James Pohl, ruled earlier that al-Nashiri could not attend despite objections from his attorneys.
Media organizations, including The Associated Press, had filed a motion urging Pohl not to close the proceedings.
Al-Nashiri is charged with masterminding the 2000 attack on the USS Cole in Yemen, which killed 17 sailors. Al-Nashiri, 47, has been held at the U.S. Naval Base in Guantanamo Bay, Cuba, since 2006 after being held by the CIA in a series of secret prisons. He is considered one of the most senior leaders in al-Qaida.