Washington may deploy as many as "thousands" of troops along the US border with Mexico, but declined to name a specific figure, Reuters has reported, citing an anonymous official.
The Pentagon declined to comment on the deployment figures, saying planning was still underway.
Donald Trump tweeted about the caravan on Monday morning, writing that "Many Gang Members and some very bad people are mixed into the Caravan heading to our Southern Border," asking them to "Please go back" and warning that "our Military is waiting for you!"
Earlier, the Wall Street Journal reported that up to 5,000 troops would be deployed to the sensitive border area, up from the initially reported estimates of between 800 and 1,000 active duty troops expected to be sent to assist with border security.
On Sunday, Pentagon Chief Jim Mattis confirmed that the military was deploying concrete barriers to the border. About 2,000 National Guard forces are already stationed in the area, with the military set to provide additional logistical assistance, including air support, equipment, vehicles and tents.
Trump has vowed to stop the caravan, characterizing its approach toward the US as a national emergency and slamming Mexican authorities for their failure to stop it.
Last week, the Department of Homeland Security announced the completion of the first, 3.22 km long section of the Mexico border wall, while urging lawmakers to approve additional funding for future sections of the wall and more border patrol personnel. the border wall is one of President Trump's signature projects, and was announced during his first speech announcing his bid for the presidency. Trump initially hoped to force Mexico City to pay for the wall's construction, and turned to Congress after Mexico's president rejected the suggestion. The president has since threatened to reject a funding measure necessary to prevent another government shutdown after December 7 if the White House doesn't get the wall construction funding it needs.