The hearing at the military facility at Guantanamo Bay, Cuba, scheduled to last for eight days, was to address defense and prosecution questions in the trial of Abd al-Rahim al-Nashiri, the Miami Herald reported.
Al-Nashiri's trail is set to begin in September, but his attorney, Rick Kammen, told the Army judge, Col. James L. Pohl, the defendant wanted to fire him.
Pohl agreed to allow Kammen to work with al-Nashiri for two days in an attempt to save their relationship.
The prosecutor, Navy Cmdr. Andrea Lockhart, asked Pohl to question al-Nashiri directly, but the judge declined.
If convicted, al-Nashiri, 49, could face the death penalty.
Al-Nashiri, who claims to be a Saudi businessman, was captured in the United Arab Emirates in 2002.