President Trump speaks during a rally in Grand Rapids, Mich., on March 28, 2019.

Faced with rising numbers of migrants at the southern border, President Trump has regaled supporters with increasingly apocalyptic warnings of an “invasion” populated by criminals with face tattoos who look fearsome enough to be “fighting for the UFC.”

“Some of the roughest people you’ve ever seen,” Trump declared in a speech to the Republican Jewish Coalition in Las Vegas last month.

But on Wednesday, in an emergency plea to Congress for $4.5 billion, his administration described the migrants as vulnerable families and children whose dire situation requires the resources “to sustain critical and lifesaving missions.”

“Immediate emergency action is required . . . to safely, securely, and humanely process and care for this at-risk migrant population,” Russell T. Vought, the acting director of the Office of Management and Budget, wrote in the emergency request to lawmakers.

The sharp dichotomy between the president’s rhetoric and the tone of his aides reflects how they are waging a battle on separate fronts — one political and the other operational — as the administration struggles to deal with a mounting humanitarian crisis at the U.S. border with Mexico.

Trump, seeking to consolidate his conservative base ahead of his reelection campaign, has escalated his attacks on the migrants as dangerous lawbreakers intent on exploiting U.S. asylum laws.

In the president’s telling, lawyers coach the migrants, most coming from Central America, into making false claims that they face political persecution and are fleeing their homelands for their safety. They abuse a lenient system, he claims, to game immigration judges into letting them stay.

“I am very afraid for my life. I am afraid for my life,” Trump said at a rally in Grand Rapids, Mich., in late March, mimicking a hypothetical migrant. “And then I look at the guy — he looks like he just got out of the ring, he’s a heavyweight champion of the world. It’s a big fat con job, folks.”

Trump, who launched his presidential campaign in 2015 by referring to immigrants from Mexico as “rapists,” has long sought to paint migrants as dangerous. He has inflated the number of violent crimes committed by undocumented immigrants and highlighted sensational murder cases during a prime-time Oval Office address in January.

Critics said the rhetoric offers Trump cover for pursuing hard-line, unilateral actions, such as his declaration of a national emergency in February to divert federal funds to build a border wall. In recent weeks, Trump and his top domestic policy adviser, Stephen Miller, have set their sights on dismantling the asylum system in a bid to dissuade migrants from coming and speed up deportations of those already here.

This week, in an executive memorandum, the president instructed the departments of Homeland Security and Justice to develop regulations to charge asylum seekers fees and deny them work permits as they await their hearings in immigration court.

“The asylum program is a scam,” Trump said in his Las Vegas speech. “How stupid can we be to put up with this?”

Trump’s “continued portrayal of the asylum seekers as somehow gaming the system is completely inaccurate,” said Gregory Chen, advocacy director at the American Immigration Lawyers Association. “In fact, most of the people who come here have very little, if any, knowledge of our legal system and what asylum even is.”

Chen argued that lawyers help facilitate the legal proceedings, suggesting that migrants are more likely to show up for court hearings if they understand the process and are better prepared to present documents in support of their claims, avoiding potential delays.

The number of migrants who have applied for asylum has soared over the past half-decade, as immigration patterns have changed. Under U.S. laws, Central American families with children cannot be detained more than 20 days, and most are released into the country as they await their asylum hearings, a process that can take more than a year because of court backlogs.

While violent-crime rates in Guatemala, Honduras and El Salvador are among the world’s highest, migrants also are fleeing economic hardship and climate change that has contributed to crop failure and hunger, experts said. U.S. laws do not grant asylum on those grounds.

Federal agencies, including Customs and Border Protection and Health and Human Services, have become overwhelmed as they have tried to adapt to the influx of a more vulnerable population. Of the 103,000 migrants apprehended at the southern border in March — the highest monthly total in a dozen years — more than half were families, according to government statistics.

In December, two migrant children died in CBP custody, prompting then-Homeland Security Secretary Kirstjen Nielsen to implement new safeguards. In his funding request Wednesday, Vought stated specifically that it is the increasing number of families and children that necessitates an emergency response. He made no mention of criminals or gangs.

Yet last month, as the number of border arrests continued to climb, Trump announced he wanted to go in a “tougher direction,” forcing Nielsen to resign and replacing her with Kevin McAleenan, the CBP commissioner.

Privately, McAleenan has told associates that his biggest fear is having another child die in federal custody. But that concern was not on Trump’s mind during a speech to the National Rifle Association in Indianapolis last week.

Calling on Democrats to amend asylum laws, Trump called the programs “horrible” and said the migrants coming in are “rough, tough MS-13 gang members.”

“You don’t want to meet with these people,” he said.

Wendy Young, president of Kids in Need of Defense, said migrant children “are very fearful” of Trump’s rhetoric.

“They feel like they are not wanted here,” she said, “and that the government does not believe them.”