Washington - The White House signaled Monday that it expects to deport most of the unaccompanied minors entering the country illegally across the southern border, employing the strongest rhetoric to date to indicate that an influx of thousands of Central American migrants will not be tolerated.

The tougher tone came a day before Obama administration officials were expected to ask Congress to authorize new measures, including more than $2 billion in emergency funds, that would expedite the legal processing of the more than 52,000 children and 39,000 families apprehended this year.

Officials said the request is separate from statutory changes that the administration is also seeking to make it easier to deport children back to Guatemala, El Salvador and Honduras, where most of the influx has originated.

The moves come as President Barack Obama attempts to stem an escalating border crisis that has caught the administration unprepared as he gets ready to announce potentially broad changes to U.S. immigration policies. The administration's rhetoric has upended traditional political alliances on the issue, drawing rebukes from Democratic allies and advocates who fear that the children will be returned to violent and impoverished countries.

More than 100 immigrant rights activists, including some undocumented children who arrived in the country recently, marched outside the White House gates Monday in protest of the administration's deportation policies.

White House press secretary Josh Earnest emphasized that the administration is committed to abiding by the law in dealing with the minors, saying each will have a chance to make a case for legal protections in immigration court.

But Earnest said that "it's unlikely that most of the kids who go through this process will qualify for humanitarian relief, which is to say that most of them will not have a legal basis . . . to remain in this country."

House Republican leaders, including Speaker John Boehner of Ohio, said they would reserve judgment on the administration's fiscal request until they see the details.

Felix Browne, a spokesman for Republican Texas Gov. Rick Perry, said that the increased funding is a "step in the right direction" if it beefs up border patrols, adding that Perry has warned Obama for years about the need to step up enforcement efforts in the region.

Obama is set to visit Dallas and Austin this week for a series of Democratic fundraisers, and he will talk about the economy at another event in Austin. But aides said the president will not visit the border in the Rio Grande Valley region, where most of the children and families are arriving, because he already has been fully briefed on the situation.

"This is not about optics. This is about solving a serious problem facing our country," Browne said in an email. "A trip by President Obama to see firsthand the humanitarian and national security crises unfolding in the Rio Grande Valley would be a valuable experience and help convey to the American people that he is truly committed to securing our nation's border."

Sen. John Cornyn, R-Texas, who last week toured a Border Patrol facility in McAllen, Texas, said in a speech on the Senate floor Monday that Obama "would prefer to hang out with campaign donors and other political supporters" rather than get a firsthand view of the border.

During his briefing, Earnest noted that officials from the Department of Homeland Security, the Federal Emergency Management Agency, and the Department of Health and Human Services have visited the region.

"The president's well aware of what's happening along the southwest border," Earnest said. "It's my view - and I don't think that this is unreasonable - that those who share the president's concern about this situation will be supportive of ensuring that the administration has the resources necessary to deal with the situation."

The fiscal request will not include details about other measures that the administration said last week it would pursue, according to administration officials and lawmakers. The administration has told Congress that it wants statutory changes to make it easier to return children to Central America.

Under anti-human-trafficking laws signed by President George W. Bush in 2008, unaccompanied minors from non-contiguous countries are afforded greater legal protections than those who arrive illegally from Mexico or Canada. They are usually placed in the care of relatives, but many do not show up for their court hearings, which are routinely delayed for more than a year because of backlogs, officials said.

Democrats have balked at rolling back those protections. Late last week, 225 organizations led by the American Civil Liberties Union sent a letter to Obama warning that eliminating those safeguards could ultimately jeopardize the children's lives.

Sen. Robert Menendez, D-N.J., who helped write a comprehensive immigration bill that passed the Senate last year, said he would support providing the administration with additional fiscal resources.

He cautioned, however, that he has "serious concerns about rolling back or diluting any domestic legal requirements specifically designed to protect due process and prevent human rights violations."

Obama told advocates in an emotional meeting at the White House last week that he is resolute in the need to deter child migrants because of the dangers involved in the journeys from their home countries. Some have reportedly died or been abused by smugglers en route.

But Wendy Young, executive director of Kids in Need of Defense, which connects unaccompanied children with lawyers, said that what the White House has "failed to recognize is that this is more of a refugee movement than an immigration wave."

"So far what we're hearing from them is deter, detain and deport, and what I haven't heard from them at all is protection," she said. "I frankly find it perplexing that they've opened this Pandora's box on themselves because immigration is an issue that has united the Democratic Party. So why they want to pick a fight with their own party on the Hill - I don't get it."