Active duty military troops will begin arriving in El Paso, Texas, and San Diego on Thursday evening, in what defense officials said is the first batch of the new forces being deployed to secure the southern border.

Troops will begin arriving on Thursday evening in what defense officials said is the first batch of new forces headed to the border.

The U.S. Pentagon is sending an additional 1,500 active-duty troops to the southern border by the end of the week, a senior U.S. military official told Fox News.

The I Marine Expeditionary Force is made up of about 53,000 active-duty troops, who are primarily stationed at Camp Pendleton, as well as at Marine Corps Air Stations Miramar and Yuma, and the Marine Corps Air/Ground Combat Center at 29 Palms, California.

The president has directed the U.S. military to reinforce the border, and the acting secretary of defense on Wednesday announced the Pentagon is sending around 1,500 active duty troops to the country’s southern border, joining 2,500 active duty personnel already there.

U.S. officials say the Pentagon will begin deploying as many as 1,500 active duty troops to help secure the southern border in the coming days.

A U.S. Border Patrol agent killed during a traffic stop near the Canadian border worked security duty at the Pentagon during the time of the Sept. 11 attacks.

The Senate on Thursday voted to advance Pete Hegseth's nomination to be President Donald Trump's defense secretary, putting him on a path to final confirmation at the end of the week.

The Pentagon said it has begun deploying 1,500 active duty troops to the southern border, including 500 Marines from Camp Pendleton.

Robert Salesses is a retired Marine who served in the Gulf War and has been deputy director of the Pentagon’s Washington Headquarters Service.

The deployment signals the military’s increased role in a much more aggressive immigration policy under the second Trump administration.

WASHINGTON (AP) — It is unclear who will take over at the Pentagon and the military services when the top leaders all step down Monday as President-elect Donald Trump is sworn into office.