White House Chief of Staff Denis McDonough said on Sunday that President Barack Obama will make good on his promise to close the Guantanamo Bay detainee facility in Cuba before the end of his presidency, saying Obama said he feels an obligation to his successor to do so.

"He feels an obligation to his successor to close that, and that's why we're going to do it," the chief of staff said on "Fox News Sunday." 

Obama pledged during his 2008 presidential election campaign that he would close the military prison which was used in the aftermath of 9/11 to get suspected terrorists off the battlefield. That vow has been a feature of his annual State of the Union addresses ever since.

The president says the facility has long since outlived its usefulness and is at times counterproductive, being used by terrorist groups like al-Qaeda as propaganda for recruitment drives. Another issue is that the prison is too expensive, with the costing the U.S. an estimated $400-450 million per year, reported the New York Daily News.

In an effort to combat this, Obama has whittled away the Guantanamo Bay population throughout his presidency, leaving the prison with only 104 detainees. There is a small number of detainees whom the administration would like to detain in a U.S. facility due to fears that they would return to terrorism should they be sent to the Middle East. However, Congress has explicitly banned the transfer of detainees to the United States, making his task that much harder.

McDonough said the president will present Congress with a detailed plan to close the prison but declined to confirm whether Obama will use executive orders to close the facility like he had tried to do with immigration and gun control issues when Congress blocked his efforts in the past.

"I'm not an 'if when' guy," McDonough said, according to Time. "The president just said he's going to present a plan to Congress and work with Congress and then we'll make some final determination."