The commander of the U.S. prison at Guantánamo Bay Naval Base in Cuba has been fired.

Rear Adm. John Ring, commander of Joint Task Force-Guantánamo, was relieved of duty Saturday following an investigation, according to the New York Times. Adm. Craig Faller made the call due to a “loss of confidence in his ability” to continue running the prison, which houses some of the most infamous terrorists in the world.

It is not immediately known what prompted the investigation or what it uncovered. Col. Amanda Azubuike, a spokeswoman for the Southern Command, said the decision was unrelated to a recent visit by members of the news media. She also said the change would not affect operations at the prison.

“This change in leadership will not interrupt the safe, humane, legal care and custody provided to the detainee population at GTMO,” military officials said in a statement.

Ring, who has led the facility since April of last year, will be replaced in an acting capacity by Brig. Gen. John F. Hussey, his deputy. Ring was commissioned in 1988 through the University of Arizona's Naval Reserve Officer Training Corps program. During his tenure, Ring served as commanding officer of the USS Comstock from 2011 to 2013 and of the USS Nimitz from 2014 to 2017. He has received a number of awards and commendations during his decades in the military.

Guantánamo Bay prison currently holds 40 detainees, down from a high of more than 600, and has had 18 commanders since it was opened in 2002 by President George W. Bush as a holding area for terrorists captured overseas.

Some of those detained are alleged to have been involved with planning and execution of the Sept. 11, 2001, terror attacks. Many of the detainees were involved in Islamist terror organizations prior to their capture.

The facility has become a political talking point over the years. Despite efforts by President Barack Obama to close the facility, after being elected in 2016 President Trump insisted it would remain open. Last year officials were told to draw up plans to keep the center going for another 25 years, through 2043. It is unclear what will be done about the prisoners who are being held there indefinitely as they begin to age and need further medical treatment.

In addition to the prison, Guantánamo Bay has a Navy base with about 1,700 troops stationed there.