File Photo: A U.S. Border Patrol agent stands in front of the border fence that divides the U.S. and Mexico in San Diego, California, the United States, Nov. 17, 2018. (Xinhua/Zhao Hanrong)

WASHINGTON, Feb. 3 (Xinhua) -- The Pentagon announced Sunday that it is deploying 3,750 more active-duty troops to the U.S.-Mexico border for three months to support border agents.

The deployment will raise the total active duty forces supporting U.S. Customs and Border Protection agents to approximately 4,350, according to a statement released by the Pentagon.

"Additional units are being deployed for 90 days, and we will continue to evaluate the force composition required to meet the mission to protect and secure the southern border," the statement said.

The announcement came as bipartisan lawmakers are trying to negotiate a deal on border security funding with a view to averting another partial government shutdown.

U.S. President Trump has repeatedly floated the idea of declaring a national emergency if the deal doesn't include money for a border wall with Mexico, a plank of his 2016 presidential campaign.

Such a declaration would enable him to bypass congressional approval and redirect funds already allocated by lawmakers for other purposes, possibly at the Pentagon, to his wall, but it is almost certain to draw political backlash and legal challenges.

In a CBS interview aired on Sunday, Trump said he doesn't "take anything off the table."

The lack of an agreement between the White House and Congressional Democrats on the border wall funding had led to a historic 35-day partial government shutdown that ended on Jan. 25.

Trump initially ordered the deployment of thousands of active-duty troops to the border with Mexico in October last year to deter members of a caravan of Central American migrants from illegally entering the United States.

The move, carried out shortly before the November midterm elections, was embraced by Trump's allies and supporters, while critics slammed it as "a political stunt."

Acting Defense Secretary Patrick Shanahan approved the latest deployment in January to fulfill a request from the Department of Homeland Security for assistance.

The Pentagon said it is "transitioning its support at the southwestern border from hardening ports of entry to mobile surveillance and detection, as well as concertina wire emplacement between ports of entry."

The new troops, the Pentagon said, will be used to install additional wire barriers and provide a large new system of mobile surveillance and monitoring of the border area.

The effort announced Sunday is separate from the potential White House-led effort to use existing Pentagon resources to help build new sections of the border wall, according to CNN.