Kirby added during a briefing that it is a Defense Department policy "to neither confirm nor deny the presence or absence of nuclear weapons at any specific location."
"The Department of the Air Force is investigating the suitability of information shared via study flashcards… All US weapons are safe and secure," he said.
Last week, the Bellingcat investigative website reported that US soldiers tasked with guarding nuclear weapons in Europe used publicly visible flashcard applications and inadvertently revealed a multitude of sensitive security protocols about American nuclear weapons and the bases in which they are stored.