GUANTANAMO BAY NAVAL BASE, Cuba — Two Sept. 11 defendants delayed the start of their hearing Monday at Guantanamo when they refused to respond to questions from their judge in the case.

Defense lawyers didn’t say what prompted the silent protest by self-proclaimed terrorist mastermind Khalid Sheikh Mohammed and one of five co-defendants at the military tribunal on the US base in Cuba. Mohammed refused to say whether he approved the hiring of another attorney for him. Fellow defendant Walid bin Attash refused to say why he wanted a military lawyer removed from his team.

Their silence Monday delayed by about an hour the start of a four-day hearing on pretrial motions for the five Guantanamo prisoners charges in the death penalty case. The judge eventually granted the changes without statements from the men.