President Donald Trump is strongly defending the U.S. use of tear gas at the Mexico border to repel a crowd of migrants that included angry rock-throwers and barefoot, crying children.

　　Migrants run from tear gas launched by U.S. agents, amid photojournalists covering the Mexico-U.S. border, after a group of migrants got past Mexican police at the Chaparral crossing in Tijuana, Mexico, Sunday, Nov. 25, 2018. The mayor of Tijuana has declared a humanitarian crisis in his border city and says that he has asked the United Nations for aid to deal with the approximately 5,000 Central American migrants who have arrived in the city. [Photo: AP/Rodrigo Abd]

　　Critics denounced the action by border agents as overkill, but Trump kept to a hard line.

　　"They were being rushed by some very tough people and they used tear gas," Trump said Monday of the previous day's encounter. "Here's the bottom line: Nobody is coming into our country unless they come in legally."

　　President Donald Trump calls on a reporter as he speaks to members of the media before boarding Marine One on the South Lawn of the White House in Washington, Monday, Nov. 26, 2018, for a short trip to Andrews Air Force Base, Md., and then on to Mississippi for rallies. [Photo: AP /Andrew Harnik]

　　At a roundtable in Mississippi later Monday, Trump seemed to acknowledge that children were affected.

　　"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?" the president asked.

　　He said it was "a very minor form of the tear gas itself" that he was assured was "very safe."

　　A group of migrants gather at the Chaparral border crossing in Tijuana, Mexico, Sunday, Nov. 25, 2018, as they try to pressure their way into the U.S. The mayor of Tijuana has declared a humanitarian crisis in his border city and says that he has asked the United Nations for aid to deal with the approximately 5,000 Central American migrants who have arrived in the city. [Photo: AP/Rodrigo Abd]

　　Without offering evidence, Trump claimed some of the women in Sunday's confrontation are not parents but are instead "grabbers" who steal children so they have a better chance of being granted asylum in the U.S.

　　On Tuesday, U.S. authorities lowered the number of arrests during the confrontation to 42 from 69. Rodney Scott, chief of the Border Patrol's San Diego sector, said the initial count included some arrests in Mexico by Mexican authorities who reported 39 arrests.

　　A Central American migrant is stopped by U.S. agents who order him to go back to the Mexican side of the border, after a group of migrants got past Mexican police at the Chaparral crossing in Tijuana, Mexico, Sunday, Nov. 25, 2018, at the border with San Ysidro, California. The mayor of Tijuana has declared a humanitarian crisis in his border city and says that he has asked the United Nations for aid to deal with the approximately 5,000 Central American migrants who have arrived in the city. [Photo: AP/Pedro Acosta]

　　Scott also defended the agents' decisions to fire tear gas into Mexico, saying they were being assaulted by "a hail of rocks."

　　"That has happened before and, if we are rocked, that would happen again tomorrow," he told reporters.

　　The showdown at the San Diego-Tijuana border crossing has thrown into sharp relief two competing narratives about the caravan of migrants who hope to apply for asylum but have gotten stuck on the Mexico side of the border.

　　Trump portrays them as a threat to U.S. national security, intent on exploiting America's asylum law. Others insist he is exaggerating to stoke fears and achieve his political goals.

　　The sheer size of the caravan makes it unusual.

　　"I think it's so unprecedented that everyone is hanging their own fears and political agendas on the caravan," said Andrew Selee, president of the Migration Policy Institute, a nonpartisan think tank that studies immigration. "You can call it scary, you can call it hopeful, you can call it a sign of human misery. You can hang whatever angle you want to on it."

　　Trump rails against migrant caravans as dangerous groups of mostly single men. That view figured heavily in his speeches during the midterm election campaign, when several were hundreds of miles away, traveling on foot.

　　The city of Tijuana said that as of Monday, 5,851 migrants were at a temporary shelter, 1,074 were women, 1,023 were children and 3,754 were men, including fathers traveling with families, along with single men.

　　The U.S. military said Monday that about 300 troops who had been deployed in south Texas and Arizona as part of a border security mission have been moved to California for similar work.

　　The military's role is limited largely to erecting barriers along the border and providing transportation and logistical support to Customs and Border Protection.

　　Democratic lawmakers and immigrant rights groups blasted the tactics of border agents.

　　"These children are barefoot. In diapers. Choking on tear gas," California Gov.-elect Gavin Newsom tweeted. "Women and children who left their lives behind — seeking peace and asylum — were met with violence and fear. That's not my America."

　　U.S. Customs and Border Protection Commissioner Kevin McAleenan said the administration's concerns about the caravan "were borne out and on full display" Sunday.

　　McAleenan said hundreds — perhaps more than 1,000 — people attempted to rush vehicle lanes at the San Ysidro crossing. Mexican authorities estimated the crowd at 500. The chaos followed what began as a peaceful march to appeal for the U.S. to speed processing of asylum claims.

　　McAleenan said four agents were struck with rocks but were not injured because they were wearing protective gear.

　　A migrant carrying a roll of carpet wipes his face after U.S. border agents fired tear gas at a group of migrants who had pushed past Mexican police at the Chaparral border crossing in Tijuana, Mexico, Sunday, Nov. 25, 2018. The mayor of Tijuana has declared a humanitarian crisis in his border city and says that he has asked the United Nations for aid to deal with the approximately 5,000 Central American migrants who have arrived in the city. [Photo: AP/Ramon Espinosa]

　　Border Patrol agents launched pepper spray balls in addition to tear gas in what officials said were on-the-spot decisions made by agents. U.S. troops deployed to the border on Trump's orders were not involved in the operation.

　　"The agents on scene, in their professional judgment, made the decision to address those assaults using less lethal devices," McAleenan told reporters.

　　The scene was reminiscent of the 1980s and early 1990s, when large groups of migrants rushed vehicle lanes at San Ysidro and overwhelmed Border Patrol agents in nearby streets and fields.

　　The scene on Sunday left many migrants feeling they had lost whatever possibility they might have had for making asylum cases.

　　Isauro Mejia, 46, of Cortes, Honduras, looked for a cup of coffee Monday morning after spending Sunday caught up in the clash.

　　"The way things went yesterday ... I think there is no chance," he said.

　　Mexico's Interior Ministry said in a statement it would immediately deport the people arrested on its side of the border and would reinforce security.

　　Border Patrol agents have discretion on how to deploy less-than-lethal force. It must be "objectively reasonable and necessary in order to carry out law enforcement duties" and used when other techniques are insufficient to control disorderly or violent subjects.