The FBI uploaded 27 photos to its website's "FBI Records: The Vault" section, showing the horrific aftermath at the facility, located in Arlington County, Virginia.
189 people died at the Pentagon, including 125 who worked at the building, which serves as the headquarters of the Department of Defense.
The plane hit an area of the building that was under renovation and relatively empty. It's widely agreed that the death toll would have been significantly higher had the plane hit a different area of the building.
Photos show fragments of the American Airlines aircraft, the gaping hole in the building left by the plane, as well as the Pentagon's scorched interior and exterior.
Other photos show first responders battling the blaze and surveying the damage.
Editor’s note: After publication of this story, an FBI spokeswoman told the AP that the photos were first posted online in 2011 and re-released in recent days after they disappeared from the site.