Demonstrators take part in a protest near the Mexico-U.S. border during U.S. President Donald Trump's inspection of the prototypes for the border wall, in Tijuana, Mexico, March 13, 2018. (Xinhua Photo)

WASHINGTON, April 4 (Xinhua) -- U.S. President Donald Trump will sign a proclamation on Wednesday directing the deployment of the National Guard to the country's border with Mexico, Homeland Security Secretary Kirstjen Nielsen said.

"The President has directed that the Department of Defense and the Department of Homeland Security work together with our governors to deploy the National Guard to our southwest border," Nielsen told a White House news briefing.

"The president will be signing a proclamation to that effect today," she said.

Troops could be sent to the border as early as Wednesday night, Nielsen said, adding that the National Guard would support U.S. Custom and Border Protection but would not be involved in enforcement.

Though Nielsen did not detail the number of those deployed, where they will go, how long they will stay, or the cost of the operation, she said the administration would be asking Congress to provide the legal authority and resources to address "this crisis at our borders."

The announcement came after days of Trump's public fuming over the immigration policy and border security as a result of what he sees "weak" border laws.

A U.S. border patrol truck is seen next to U.S. President Donald Trump's border wall prototypes from the U.S.-Mexico border in Tijuana, northwestern Mexico, on April 3, 2018. (Xinhua/AFP )

The president, who has signaled intentions to use the military to guard the border until his long-promised wall is built, tweeted earlier Wednesday that the administration will be "taking strong action today."