CNN

WASHINGTON (CNN) – The investigation into last week's shooting rampage at Fort Hood will be a "thorough accounting," Defense Secretary Robert Gates pledged.

"The president and I are committed to a thorough accounting of what happened, and to seeing that the shooting victims and their families have everything they need to recover from this ordeal," Gates said Tuesday at a Library of Congress event honoring President Ronald Reagan's contribution to the fall of the Berlin Wall.

"Tomorrow is Veterans Day, when we paused to remember the contributions and the sacrifices of all who have worn America's uniform," Gates said, adding that "America's family remains in mourning" over last week's rampage. He called for a moment of silence "for those so ruthlessly attacked at Fort Hood last week, and their families, and out of gratitude (for) veterans who have served in defense of their country."

He participated in a memorial service Tuesday at Fort Hood, honoring the 13 who died during the rampage, but he did not speak.

On Monday night, he visited Fort Hood to meet with the victims' families, as well as Fort Hood police Sgt. Kimberly Munley, who disabled the gunman as they shot at each other.

Gates also was slated to meet with military officials at the Army base, including Fort Hood's commanding general, Lt. Gen. Robert Cone, and Chairman of the Joint Chiefs of Staff Adm. Mike Mullen.