A state's government is overthrown by a group of people from within the state's own armed forces.

Examples:
In "Akira" (1988), Colonel Shikishima led a coup d'état against the Neo Tokyo government and directed all of its military forces to destroy a young man who had acquired near god-like telekinetic abilities.

References:
https://en.wikipedia.org/wiki/Coup_d%27%C3%A9tat