The memo builds on Trump’s declaration of a national emergency at the southern border on Inauguration Day. The declaration ordered a report within 90 days from Defense Secretary Pete Hegseth and Homeland Security Secretary Kristi Noem “about the conditions at the southern border of the United States and any recommendations regarding additional actions that may be necessary to obtain complete operational control of the southern border, including whether to invoke the Insurrection Act of 1807.”

Trump’s memo authorizes the Pentagon to exert jurisdiction on federal lands, including the Roosevelt Reservation along the southern borders of California, Arizona, and New Mexico. It does, however, exclude federal Native American reservations “that are reasonably necessary to enable military activities … including border-barrier construction and emplacement of detection and monitoring equipment.”

The order also provides for the “transfer and acceptance of jurisdiction over such Federal lands in accordance with applicable law to enable military activities … to occur on a military installation under the jurisdiction of the Department of Defense and for the designation of such Federal lands as National Defense Areas by the Secretary of Defense.”

It authorizes Hegseth to “determine those military activities that are reasonably necessary and appropriate to accomplish the mission assigned” in Trump’s Inauguration Day executive order titled “Clarifying the Military’s Role in Protecting the Territorial Integrity of the United States.”

In conducting activities outlined in the presidential memo, “members of the Armed Forces will follow rules for the use of force prescribed by” Hegseth.

The memo orders Hegseth, Noem, Interior Secretary Doug Burgum, and Agriculture Secretary Brooke Rollins to “initially implement this memorandum on a limited sector of Federal lands designated” by the Defense secretary.

Within 45 days, Hegseth “shall assess this initial phase” and at any time can “extend activities … to additional Federal lands along the southern border in coordination Noem, Stephen Miller, Trump’s Homeland Security adviser, “and other executive departments and agencies as appropriate,” the memo adds.

Following Trump’s Inauguration Day emergency declaration, the Pentagon reportedly deployed an additional 1,500 troops to reinforce the 2,500 already stationed at the southern border during the Biden administration. Further steps soon followed, including the transfer of the 10th Mountain Division headquarters—along with its commanding officer, Maj. Gen. Scott Naumann—from Fort Drum in New York to Fort Huachuca in southeastern Arizona to lead the mission.

Naumann now oversees approximately 6,600 troops under the banner of Joint Task Force Southern Border, Newsmax reported.

For now, the role of active-duty military personnel at the southern border remains primarily supportive, assisting Customs and Border Protection with surveillance and detection, The Washington Post reported Friday. Under the 1878 Posse Comitatus Act, active-duty troops are generally prohibited from engaging in direct law enforcement activities, including detaining illegal immigrants, except in limited circumstances.

The memo comes as illegal border crossings have sharply declined since the beginning of President Trump’s second term. In March, Customs and Border Protection recorded 7,180 crossings at the southern border—down from a monthly average of 155,000 over the previous four years.

Daily apprehensions have also dropped to about 230, representing a 95% decrease from the Biden administration’s average of 5,100 per day.

A federal judge on Friday dismissed a lawsuit brought by churches challenging the Trump administration’s new policy permitting immigration officers to make arrests near churches, ruling that the religious groups failed to demonstrate sufficient harm to justify legal action.