WASHINGTON, Nov. 19 (Xinhua) -- The U.S. Department of Defense Thursday ordered a major review of the shootings in an Army base earlier this month.

Defense Secretary Robert Gates told a press conference that the review would check if the military had missed any warning signs and what it can do to prevent such shootings from being repeated.

    He referred to the Nov. 5 massacre in Fort Hood, an Army base in Texas, where a 39-year-old military psychiatrist, Maj. Nidal Hasan, killing 13 and wounding over 30 others.

Nidal Malik Hasan, the suspect in last week's mass shooting incident at Fort Hood army base, Tex

    "We do not enter this process with any preconceived notions," Gates said. "However, it is prudent to determine immediately whether there are internal weaknesses or procedural shortcomings in the department that could make us vulnerable in the future."

    The defense secretary named former Army Secretary Togo West and former chief of naval operations Vernon Clark to lead the review.

    According to U.S. media reports, Hasan was under watch before the killings but the investigation was ceased for some unknown reason.

    New evidence was found that Hasan had been in contact with someone on a U.S. "kill or capture" list of al-Qaida and Taliban targets, said the reports.

    President Barack Obama has already ordered an investigation to look at how intelligence in the case was handled and shared among agencies.

    The Army and the Senate have also started their own investigation into the case, respectively.