Late in life, a former Pentagon chief is on a mission to warn of dangers unseen by US public

FILE - In this Aug. 2010 file photo, former Defense Secretary William Perry testifies on Capitol Hill in Washington. The 88-year-old former defense secretary is troubled by the risks of catastrophe from the very weapons he helped develop decades ago. Atop his worry list: a nuclear terror attack in a major U.S. city or a shooting war with Russia that, through miscalculation, turns nuclear. A terrorist attack using a nuclear bomb or improvised nuclear device could happen “any time now – next year or the year after,” he said in an interview with reporters earlier this month.(AP Photo/Alex Brandon, File) (The Associated Press)

FILE - In this June 25, 2014 file photo, an inert Minuteman 3 missile is seen in a training launch tube at Minot Air Force Base, N.D. The base is tasked with maintaining 150 of the nuclear-tipped missiles spread out across the North Dakota countryside and keeping them ready to launch at a moment's notice as part of the US's nuclear defense strategy. William Perry, the 88-year-old former defense secretary is troubled by the risks of catastrophe from the very weapons he helped develop decades ago. Atop his worry list: a nuclear terror attack in a major U.S. city or a shooting war with Russia that, through miscalculation, turns nuclear. A terrorist attack using a nuclear bomb or improvised nuclear device could happen “any time now – next year or the year after,” he said in an interview with reporters earlier this month. (AP Photo/Charlie Riedel, File) (The Associated Press)

WASHINGTON – Late in a life lived unnervingly near the nuclear abyss, William J. Perry is on a mission to warn of a "real and growing danger" of nuclear doom.

The 88-year-old former defense secretary is troubled by the risks of catastrophe from the very weapons he helped develop decades ago.

Atop his worry list: a nuclear terror attack in a major U.S. city or a shooting war with Russia that, through miscalculation, turns nuclear.

He said in an interview that a terrorist attack using a nuclear bomb or improvised nuclear device could happen "any time now - next year or the year after."

Perry played a central role in developing and modernizing nuclear forces throughout the Cold War. He was a technology whiz-kid and later a three-time senior Pentagon executive.