The Department of Homeland Security (DHS) has requested for the Department of Defense (DoD) to keep 4,000 troops on the U.S.-Mexico border. The DHS wants the Pentagon to keep the troops on the border from Christmas to January 31, 2019. The DHS’s request was revealed by DoD sources who do not want to be named.

The active-duty forces will function as aviation support, military police, logistics and medics, among other border control roles.

Just last week, Defense Secretary Jim Mattis said that with the DHS request, some troops already posted to the border might be retained to the end of January 2019, and new units may be deployed, as well. Those that will be kept on at the border will be spending Thanksgiving, Christmas and New Year celebrations at the post.

DoD officials confirmed to Military Times that the DHS asked for support through January at the border post. The DHS did not request for new capabilities, but the support they asked for “refines support to ensure it remains aligned with the current threat, the nature of the mission, and [Customs and Border Protection] operational requirements,” the Pentagon wrote.

A defense source noted that the requested 4,000 soldiers is the actual troop size needed for the mission at the border, and that a significant number of them will be posted to California where migrants have gathered at the Tijuana checkpoint. According to the DoD, 2,400 troops are now in Texas, another 1,800 posted to California, and still 1,400 deployed to Arizona.