'Citadel' in the Bible

Look [at] the land of the Chaldeans! {This people no longer exists. Assyria destined} it for wild animals. They erected its siege towers; they demolished its citadel fortresses. It made her like a ruin.

And thorns shall go up her citadel fortress, weeds and thistle plants in her fortresses; and it shall be [the] settlement of jackals, green grass for [the] daughters of an ostrich.