WASHINGTON — The Defense Department released a transcript on Wednesday of what it said was an exchange that had been censored from the public video feed of a military tribunal at Guantánamo Bay, Cuba, this week. A military judge had ordered the excerpt made public.

The blocked comments came during a pretrial motions hearing on Monday in the case against Khalid Shaikh Mohammed and four other detainees accused of aiding the attacks of Sept. 11, 2001. The episode was the first public indication that censors outside the courtroom were monitoring the live video from the tribunal and that they could cut the feed, which is delayed by 40 seconds before it can be viewed by the public and reporters.

During the censored portion, according to the transcript, David Nevin, a defense lawyer, was discussing whether arguments over a motion “will turn out to be closed or secret” regarding the preservation of evidence “at a detention facility,” an issue he said was “a critical matter to Mr. Mohammed” and “central to the case as far as he is concerned.”

The lawyers then became aware that a red light had gone on, indicating that the courtroom had been closed. But the button in the courtroom had not been hit by the only previously known censor, a security officer who sits near the judge, Col. James Pohl of the Army.