The man who claims to be the mastermind behind the Sept. 11 attacks repeatedly declined to answer a judge's questions Saturday at a military tribunal at Guantanamo Bay.

Khalid Sheikh Mohammed and four other men appeared for the first time in more than three years for arraignment. The men are charged with 2,976 counts of murder for the 2001 attacks.

But before the arraignment could even begin, the defendents caused choas in the courtroom.

The men took off the earphones that provide Arabic translations and refused to answer any questions from the judge. And at one point, two of the men got up and prayed alongside their defense tables.

Family members of some of the victims were watching the proceedings via closed-circuit TV.

The men will eventually be tried in front of a U.S. military tribunal. They could get the death penalty for the 9/11 terrorist attacks that killed nearly 3,000 people.