Trump orders 1,500 troops to secure US-Mexican border

The additional US troops will supplement a contingent of roughly 2,200 active-duty personnel who are already at the border carrying out mostly logistical and bureaucratic tasks. US troops are typically prohibited from carrying out domestic law enforcement under an 1878 law known as the Posse Comitatus Act, but Trump said in an order he signed Monday that he would decide within 90 days whether he would use the Insurrection Act to override the law.

White House spokesperson Karoline Leavitt told reporters that "the American people have been waiting for such a time as this -- for our Department of Defense to actually take homeland security seriously."

"This is a number one priority of the American people, and the president has already delivered," she said.

Leavitt did not elaborate on what the US forces would be doing.

Trump on Monday signed a raft of new orders that seek to crack down on migration, including declaring a national emergency at the US-Mexican border.

His latest effort to seal the border authorizes "the Department of Homeland Security, the Department of Justice, and the Department of State to take all necessary action to immediately repel, repatriate, and remove illegal aliens across the southern border of the United States," the White House said in a statement.

"Through the exercise of his authority, President Trump has further restricted access to the provisions of the immigration laws that would enable any illegal alien involved in an invasion across the southern border of the United States to remain in the United States, such as asylum," it added.