United States President Donald Trump on Monday said security forces had to use tear gas at the Mexican border because they were "being rushed by some very tough people" but it was not used on children.
But while some are giving up their dream, others are just arriving, further stretching resources at makeshift camps.
There are reportedly more than 5,000 Central American migrants in Tijuana seeking to apply for asylum.
Trump also told Politico that he saw little need to work with Congress over immigration reforms to address the roughly 700,000 so-called Dreamers, young adults who were brought to the United States illegally as children, and would instead see how court challenges play out.
Trump has since threatened to "permanently" lose the U.S. The agency's use of tear gas has now reached a seven-year record high.
Mattis told reporters that this did not change the military's mission in any way and that he would use the new authorities only in response to a request by Homeland Security Secretary Kirstjen Nielsen.
Iraq combat veteran Bryan Suits on the migrant caravan heading toward the U.S. -Mexico border.
"Any border security and immigration policy that results in mothers and children being gassed is not only cruel and morally reprehensible, but also an abject failure", said Rep. Bennie Thompson of MS, the top Democrat on the House Committee on Homeland Security.
However, the ministry agreed to reinforce the border crossings migrants breached on Sunday.
"It's a term that's used because, as you know, many people, it's a very violent, awful thing, that they feel they have an advantage when they're with a young child, and they call them grabbers", he said. He said if resources were allocated for asylum seekers, it would slow down the process for people coming into and leaving the United States, including at global airports.
Customs and Border Protection Commissioner Kevin McAleenan said, per protocol, the decision to fire was made by agents on the scene using their professional judgment, and also per protocol the incident will be reviewed.
Mexico has offered to consider asylum claims.
Now, about 1,800 of the 5,600 active-duty troops deployed to the southwest border with Mexico are in California, according to numbers provided Monday by the Army.
"You know, you have certain advantages in terms of our insane laws that frankly Congress should be changing", he said.
"The agents responded with the least amount of force we possibly could", he said.
"We have been approached by folks who have expressed complaints", Becerra, who is the son of Mexican immigrants, said.
He described what unfolded Sunday as a "flashpoint" in what is "still a very dynamic situation".
The UN estimates that between 12,000 and 14,000 migrants have crossed the Guatemala-Mexico border, headed north to the US, since mid-October, including about 100 LGBT persons desiring to claim asylum. "This woman placed her own life and her children's lives in peril".
"People here are pretty dug in", said Rubio, a Republican.
At a round table in MS later on Monday, Trump seemed to acknowledge that children were affected, asking, "Why is a parent running up into an area where they know the tear gas is forming and it's going to be formed and they were running up with a child?" "So some people got rocks and threw them because many kids were fainting", he said.