On his first day in office, President Donald Trump made it clear that he was serious about fully securing the nation's southern border and was prepared to use the U.S. military to help accomplish that goal.

On Saturday, the Pentagon ordered the deployment of an additional 3,000 troops along with armored Stryker vehicles to the southern border to assist ongoing operations to defend the nation's territorial integrity, Breitbart reported.

Those troops and armored vehicles will bolster others who were previously deployed over the past month -- bringing the total number of troops at the border to around 9,000 -- and are providing support to federal and state agents and officials.

More troops deployed to southern border

In a statement released on Saturday, Defense Department Chief Spokesman Sean Parnell said, "As directed by President Trump, Secretary of Defense Pete Hegseth has ordered the deployment of a Stryker Brigade Combat Team (SBCT) and General Support Aviation Battalion to reinforce and expand current border security operations to seal the border and protect the territorial integrity of the United States, a priority for the President."

"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," he added.

Defense Secretary Pete Hegseth subsequently shared that statement on X and added some commentary about the deployment orders, and wrote, "We are dead serious about 100% OPERATIONAL CONTROL of the southern border."

Trump declared a national emergency at the southern border

This deployment stems directly from an executive order President Trump signed on his first day in office to declare a national emergency at the southern border in support of a mission to defend against illicit cross-border activity like illegal immigration and the smuggling of humans, drugs, and other contraband.

"America’s sovereignty is under attack," Trump's order stated. "Our southern border is overrun by cartels, criminal gangs, known terrorists, human traffickers, smugglers, unvetted military-age males from foreign adversaries, and illicit narcotics that harm Americans, including America."

"This assault on the American people and the integrity of America’s sovereign borders represents a grave threat to our Nation," the order continued. "Because of the gravity and emergency of this present danger and imminent threat, it is necessary for the Armed Forces to take all appropriate action to assist the Department of Homeland Security in obtaining full operational control of the southern border."

Trump's order went on to invoke various statutory authorities that allow for the deployment of military troops on U.S. soil in instances of national emergencies.

The order also outlined what those deployed troops would be authorized to do, namely provide support to the Department of Homeland Security in terms of personnel and equipment, and fill roles in barrier construction, communications, detention, intelligence, logistics, surveillance, and transportation, among other duties.

"The Border is CLOSED"

Separate but relatedly, in a Truth Social post on Saturday, President Trump wrote, "The month of February, my first full month in Office, had the LOWEST number of Illegal Immigrants trying to enter our Country in History -- BY FAR! There were only 8,326 apprehensions of Illegals by Border Patrol at the U.S. - Mexico Border, all of whom were quickly ejected from our Nation or, when necessary, prosecuted for crimes against the United States of America."

"This means that very few people came -- The Invasion of our Country is OVER," he continued. "In comparison, under Joe Biden, there were 300,000 Illegals crossing in one month, and virtually ALL of them were released into our Country."

"Thanks to the Trump Administration Policies, the Border is CLOSED to all Illegal Immigrants. Anyone who tries to illegally enter the U.S.A. will face significant criminal penalties and immediate deportation," the president added.