The Pentagon announced that the United States would send an additional 3,750 troops to the border with Mexico, bringing the total number of troops actually operating in the region to 4,350.
The troops were deployed mainly under an order issued by President Donald Trump before the mid-November elections, where convoys of migrants were making their way to the US border to seek asylum to escape violence and poverty in their country.
But reinforcements, including military assistance to civilian border guards by providing logistical support and installing barbed-wire fences, have been criticized as a political ploy to create an illusion of an impasse.
"The Department of Defense will deploy approximately 3,750 additional US troops to provide additional support to the Customs and Border Protection (CBP) elements on the south-western border approved by US Defense Secretary Patrick Chanahan on Jan. 11," the Pentagon said in a statement.
The deployment of additional troops is valid for three months, bringing the total number of troops deployed on the border to 4,350, the ministry said.
Their tasks will include "mobile surveillance capabilities until the end of September 2019, as well as the placement of approximately 150 miles of barbed wire between the entry ports."
The announcement comes days before Feb. 15, Trump's final promise to Congress to agree to finance the construction of a border wall that has been a key pledge in his campaign.
Trump said the existing parts of the wall should be extended along the border to stop what he called an uncontrollable invasion of criminals.
Trump returned Sunday and highlighted the allegations. "As convoys march across Mexico toward our country, Republicans must be prepared to do whatever is necessary for strong border security," wrote the wealthy property tycoon.