Defense Secretary James Mattis has a problem: where to put all those ISIS prisoners of war.

On his way to Germany for the annual Munich Security Conference, Mattis suggested it might have been easier if the ISIS fighters had died on the battlefield like they always said they wanted to.

According to the Washington Examiner, Mattis is preoccupied with where the U.S. is going to put all those surrendered forces.

“I needed to lay out the problem,” Mattis told the media assigned to cover him at the conference, where he will open the session with a speech Friday afternoon. “We have hundreds of prisoners who don’t have quite the same amount of zeal they once pronounced when they were winning that they would fight to the death. It seems like hundreds of them are not quite that committed.”

Mattis did not mention Guantanamo Bay, even though President Trump in his January State of the Union address promised to keep the detention facility open. The defense secretary told reporters that the ISIS detainees are cooling their heels in a temporary holding tank right now and that he intends to raise the issue at the Munich conference.

He said he is “under no illusion” that any quick fix can be found to alleviate the need for more prison space.

Mattis also pronounced efforts to increase the per capita defense of NATO countries to be right on course. Eight member states will achieve the two percent objective this year while another 14 are on track to get there by 2024.

“Year-on-year across the alliance, 2017 saw the largest growth … as a percentage of GDP, and the largest real growth in a quarter century,” Mattis announced.

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