Speaking at a lunch with Baltic leaders, Trump said he's been discussing the idea with his Defense Secretary, Jim Mattis. The $1.3 trillion spending package recently passed by lawmakers only includes $1.6 billion for border wall funding, and the bulk of that money must be used to fix existing parts of the wall, not for new construction.
President Donald Trump is calling for new border wall and immigration legislation, tweeting that moving to the "nuclear option" in the Senate is only way to muscle such a measure through Congress. "That's a big step", he told reporters before accusing President Barack Obama making "changes that basically created no border".
"We can not have people flowing into our country illegally, disappearing, and by the way never showing up for court", he added, referring to "catch and release" immigration policies.
The caravan, which once included about 1,150 migrants, also has been sidelined for several days at a sports stadium in the southern state of Oaxaca.
In a statement Monday, Mexico's government described the caravan as "a public demonstration that seeks to draw attention to the migratory phenomenon and the importance of respecting the rights of Central American migrants". "Only time will tell", he said.
Trump sent his tweet on the fourth day of his vacation in Palm Beach, Florida, where he has been staying at his private Mar-a-Lago Club with a small coterie of aides. "Cash cow NAFTA is in play, as is foreign aid to Honduras and the countries that allow this to happen".
DACA, which Trump ordered phased out in September, only protects immigrants brought to the United States before 2007.
Like Bush, the Democratic president hoped, in vain, that a greater military commitment would help bring Republicans to the table for negotiations that would lead to comprehensive immigration reform, including a path to citizenship for numerous estimated 11 million undocumented immigrants in the US. The current march is scheduled to end this month with a conference on migration issues in the central Mexican state of Puebla.
A group called Pueblo Sin Fronteras organized the caravan, which consists of about 1,200 people - including infants, the elderly and people facing violence in their homelands.
Trump did not offer more details, but the move appears to have been at least partly motivated by a caravan of over 1,000 Central American migrants heading toward the US border.
Many migrant advocate groups argue that given the scale of the armed law enforcement presence, the extensive surveillance infrastructure, fencing, and numerous checkpoints, the border is, in effect, already militarised. A group of about 150 men reportedly broke away and boarded a freight train after the caravan stopped, and could be trying to enter the U.S. But the rest stayed back and were unlikely to proceed until later this week.
"It is not this government's responsibility to make immigration decisions for the United States or any other country, so it will be up to the appropriate authorities of the United States to decide whether to authorize the entry of the caravan participants to USA territory", the statement said. "Pretty much everybody agrees to that, except very stupid people".