WASHINGTON - The names of all seven of the CIA operatives killed last year in Khost, Afghanistan, have been placed in the agency's "Book of Honor," meaning their secret cover has been lifted.

The five CIA staff officers and two security contractors killed Dec. 30 were memorialized Monday at CIA headquarters in Langley, Va.

They included the last victim to be publicly identified, Jennifer Lynne Matthews, 45, a mother of three, who was chief of the CIA base in Khost.

CIA Director Leon E. Panetta unveiled a total of 12 stars added to the agency's Memorial Wall, including those who died in Khost. The wall and its stars commemorate CIA employees killed since 1947.

"We take strength from their powerful example as we carry on their vital work and the vital work of this Agency," Panetta said in a statement.

The "Book of Honor" contains the names of employees who died while working for the CIA and sits directly below the wall. Next to each name is a 23-carat gold leaf star.

Even in death, some names on the wall remain secret to protect sources and methods used in gathering intelligence. Each of these officers is remembered in the book only with a gold star.

Also killed in the blast after a double agent blew himself up were CIA officers Scott Michael Roberson, 39; Harold E. Brown Jr., 37; Darren LaBonte, 35; Elizabeth Hanson, 30; and security contractors Jeremy Jason Wise, 35, and Dane Clark Paresi, 46.

The CIA said the five other stars added to the wall represented those who died in recent years while performing clandestine assignments. They were not publicly identified because details of their work remain classified.