FLORENCE, Colo. — Three officers were injured by an inmate with a makeshift weapon at the Administrative Maximum (ADX) prison facility in southern Colorado on Wednesday morning.

All three staff members were transported to a nearby hospital and treated for non life-threatening injuries, according to a press release from the prison, which is often referred to as “Supermax” and is located in Florence. Prison officials also confirmed the FBI has been notified, and that an investigation into the attack is underway.

The prison press release did not identify the inmate accused in the attack, nor did it provide any details about the homemade weapon the inmate was able to construct.

The timing of the attack, coming on the 12th anniversary of September 11th terrorist attacks on the United States, might be significant, given that many inmates in the prison have been convicted of terror plots.

That list includes Zacarias Moussaoui, a convicted conspirator of the Sept. 11 attack, Ramzi Yousef, the convicted mastermind behind the 1993 World Trade Center bombing, Terry Nicols, who was convicted of assisting Oklahoma City bomber Timothy McVeigh, and Jeff Fort, who was convicted of conspiring with Libya to perform acts of domestic terrorism on the United States.

The so-called “Unabomber,” Ted Kaczynski, and shoe bomber Richard Reid are also inmates at the prison.