The meeting is expected to be held at the military installation in Quantico, Virginia, multiple officials said, adding that no one seems to know what the meeting is about, including the general and flag officers themselves, or why it was suddenly added to the calendar.

One source familiar said they'd heard theories ranging from a group physical fitness test, to receiving a briefing on the state of the Defense Department, to a mass firing of officers, but regardless of the reason the sudden convening of so many senior military officers is highly unusual.

"It's being referred to as the general squid games," one official quipped.