Prosecutors asked Monday that three Army officers be dismissed as potential jurors in the murder trial of the Fort Hood shooting suspect because the soldiers indicated that they opposed the death penalty.

Six potential jurors -- four colonels and two lieutenant colonels -- were brought in from Army posts nationwide and overseas as questioning continued in the court-martial of Maj. Nidal Hasan. The Army psychiatrist faces execution or life in prison without parole if convicted in the 2009 rampage that left 13 dead and nearly three dozen wounded on the Texas Army post.

Hasan, 42, is serving as his own attorney. Ten potential jurors remain from a group of 20 questioned last week, when jury selection began.

The judge, Col. Tara Osborn, brought one colonel out for individual questioning before lunch. He said he struggled with the death penalty issue over moral and religious grounds.

"I question whether fallible human beings can impose death on other human beings," he said.

Osborn is expected to rule later Monday on prosecutors' requests to dismiss the three.

After the jurors were questioned as a group Monday, prosecutors requested that the three officers be dismissed. They noted that all three had indicated -- in court or in jury questionnaires -- that they opposed the death penalty and wouldn't be able to put aside those views if Hasan were found guilty. Two of the three also said they already believe Hasan is guilty.

Hasan's jury will be comprised of 13 to 16 members with ranks equal to his or higher. Death-penalty cases in the military require at least 12 jurors, more than in other cases. And unlike other trials, their verdict must be unanimous in finding guilt or assessing a sentence.

Testimony is expected to start Aug. 6.

Earlier Monday, Osborn told the group that Hasan was wearing a camouflage uniform worn by troops in combat instead of a dress uniform -- usually worn by defendants in a court-martial -- because it better meets his health-related needs as a paraplegic. Osborn told potential jurors not to hold his type of uniform against him.

Hasan was paralyzed from the abdomen down after being shot by police the day of the rampage.

Osborn also told the group Hasan was wearing a beard for his religious beliefs and not to hold it against him. Although facial hair violates Army rules, Hasan started growing a beard last summer, saying it was required by his Muslim faith.