The Associated Press has learned new details about the upcoming broad Pentagon review of the circumstances surrounding the Fort Hood shootings, which Defense Secretary Robert Gates will announce Thursday.

The announcement will include plans to bring in a former senior defense official to head the wide-ranging probe.

A senior administration official says the unified review will involve a number of components, and will call for a quick, short-term report, followed by a longer, more extensive study.

The official spoke on condition of anonymity because announcements have not yet been made.