Thousands of tired Central American migrants in a caravan that has advanced 250 miles (410 kilometers) into Mexico but remains far from the US border hope they won't have to walk anymore, at least for a while.
A USA official told Reuters that as of Wednesday the Pentagon had identified more than 7,000 active-duty troops, which included about 2,000 on standby, that could be deployed to the border with Mexico if needed.
He continues to blast the caravan of migrants as they approach the U.S. -Mexico border.
The Pentagon has announced it is sending 5,200 troops to the southwest border, with their role largely limited to such activities as providing helicopter support, installing concrete barriers and maintaining vehicles.
"We don't do stunts in this department", Mattis said on Wednesday.
Certainly Trump was back in fighting mood on Wednesday, tweeting that he and Melania "were treated very nicely yesterday in Pittsburgh". A caravan last the spring ultimately fizzled to just about 200 people who reached the US border at San Diego.More news: Pakistan moves up 11 spots in 'ease of doing business' ranking
Trump has consistently exaggerated the size of the caravan and the threat it plays to the United States.
The extraordinary military operation comes a week before the November 6 midterm elections as Trump has sought to transform fears about the caravan and immigration into electoral gains.
Trump tweeted Wednesday that Mexican soldiers were "unable or unwilling" to stop the thousands of migrants moving toward the United States border.
Pelosi explained that the migrant caravan - consisting of several thousand asylum seekers from Central America consists mainly of families, including small children - are fleeing some of the world's poorest and most violent countries.
The U.N. Refugee Agency has urged the Trump administration to allow people fleeing persecution and violence to request asylum on US territory.More news: Arsenal vs. Blackpool - Football Match Report
Mr Trump has been accused of playing up concerns over immigration to help drive up turnout among his supporters, with the Republican majorities in the Senate and House of Representatives on the line at next week's elections.
"The support that we provide to the secretary of Homeland Security is tactical support based on the request from the commissioner of customs and border police", Mattis said.
But the first caravan - which planned to take a day of rest Wednesday in Juchitan, about 900 miles from the nearest USA border crossing - is only the start.
"Democrats' position is so radical and so irresponsible", says Krikorian, "that people will recoil from it if it is presented to them in a clear-cut way".
"In a macro sense, our concept of operations is to flow in our military assets with a priority to build up southern Texas and then Arizona and then California", US Air Force Gen. Terrence John O'Shaughnessy told reporters this week.
A deployment of 15,000 would bring the military commitment on the border to roughly the same level as in war-torn Afghanistan. Trump did not say if he obtained the alleged information from US intelligence agencies, Mexican intelligence officials or right-leaning cable news outlets.More news: Turkey targets east of Syria after securing Idlib
A second, which clashed with police whiling crossing Guatemala into Mexico this week, is made up of an estimated 1,000 people.