WASHINGTON >> The Pentagon is sending about 3,000 additional troops to the southwestern border, rushing to comply with President Donald Trump’s order to increase the military’s role in stemming the flow of migrants into the United States.

Armed infantry and support troops from the 4th Infantry Division at Fort Carson in Colorado — one of the Army’s most seasoned combat units — are expected to deploy within days, two Pentagon officials said Saturday, after Trump’s declaration on his first day in office that U.S. military forces would confront what he called an “invasion” of migrants, drug cartels and smugglers.

Combined with 1,100 support troops from the military’s Northern Command announced Friday, and the recently arrived headquarters personnel from the 10th Mountain Division at Fort Drum, New York, the reinforcements announced Saturday would bring the total number of active-duty troops on the border to about 9,000, Defense Department officials said. The Washington Post reported the additional troop mobilization earlier.

“These forces will arrive in the coming weeks, and their deployment underscores the department’s unwavering dedication to working alongside the Department of Homeland Security to secure our southern border and maintain the sovereignty, territorial integrity and security of the United States under President Trump’s leadership,” the Pentagon said in a statement Saturday.

This will be the second major wave of active-duty troops sent to secure the border since Trump took office Jan. 20. About 1,600 Marines and Army soldiers arrived soon after the inauguration, joining 2,500 Army reservists called to active duty who were already there.

Dispatching large numbers of front-line combat forces indicates that Trump is breaking with past presidents’ recent practice of mostly limiting deployments along the U.S.-Mexico border to small numbers of active-duty soldiers and reservists.

So far, active-duty troops have been helping to build barriers and support law-enforcement agencies, as have active-duty and reservist forces sent to the border in past years, including during Trump’s first term.

But Defense Secretary Pete Hegseth said on his first full official day on the job in January that “whatever is needed at the border will be provided.” He did not rule out Trump’s invoking the Insurrection Act, a more than 200-year-old law, to allow the use of armed forces for law enforcement duty.

The deployments come even as the state of the border is fairly calm, with crossings having fallen sharply in recent months after the Biden administration took steps to limit migration.