The U.S. Navy is drafting plans to house up to 25,000 immigrants on its bases and other facilities, at an estimated cost of about $233 million over six months, as the Trump administration seeks to ease a mounting crisis on the Mexican border, a U.S. official said on Friday.

The navy has not so far been asked to provide accommodation for people who have entered the United States illegally. The official, who asked not to be named, stressed that the draft memo, which looks at setting up housing on navy airfields in Alabama, was for planning purposes only.

The news was first reported by Time magazine.