As the Obama administration scrambles to respond to an influx of unaccompanied minors across the Mexican border into Texas, the union that represents 16,500 border patrol officers has made its frustration clear.

“New annual job rating areas: Babysitting, Diaper Changing, Burrito Wrapping, Cleaning cells. Law Enforcement? What’s that? #lowmorale” the group wrote on its Twitter feed last weekend.

The message, posted to the National Border Patrol Council’s Twitter account, was deleted after it was decried by immigrant advocates as racist. But the tweet reflected mounting concern among rank-and-file agents who have been yanked from patrol duty in high-risk border areas to process and care for tens of thousands of children, union officials said.

“Nothing in there was racist,” union president Brandon Judd said in an interview, referring to the tweet. “All he was trying to emphasize is that we can’t do our jobs. Forty percent of our agents have been pulled from the field to babysit, clean cells, change diapers. We’re actually making burritos. That’s not our job. Our job is to protect the border.”

The union’s growing criticism of the administration’s border policies has added another sharp voice to the immigration debate in Washington, where the crisis has become the latest flash point between the two political parties. Administration officials Friday announced new measures to strengthen its border policies to stem the flow of migrants, most of whom are from Central America and have crossed through the Rio Grande Valley in recent months without their parents.

View Graphic Sudden surge in unaccompanied children at border

In recent weeks, Democrats have pointed to images of the children sleeping in crowded holding rooms to emphasize the humanitarian costs of border policies that have left millions of undocumented immigrants in legal limbo. Republicans, meanwhile, have cited the crisis as evidence that President Obama must drastically bolster border security to deter future waves of migrants from crossing illegally.

The patrol agents have lent weight to the GOP argument, warning in congressional hearings and on cable news shows that resources to combat drug and weapons trafficking have been diverted to handling the immigrant children. Judd told a House panel that the crisis is straining the border patrol “to the breaking point.”

Obama mobilized an emergency response earlier this month, directing the Department of Health and Human Services to provide care and shelter for the children and putting the Federal Emergency Management Agency in charge of coordinating the effort.

Democratic lawmakers say the border agents’ hard-line views have emboldened their GOP counterparts, contributing to the difficulties of reaching a comprehensive immigration deal in the House.

Rep. Raúl M. Grijalva (D-Ariz.), who favors a less restrictive immigration policy, said border patrol agents are “trotted out as front-line people who know immigration and think we should have enforcement until there is zero tolerance and we shouldn’t have reform. They’re beating the drum through members here and saying, ‘Look what’s happened with these kids. There are lax policies and not enough enforcement.’ ”

On some issues, the agents have directly contradicted the Obama administration, which initially cited gang-related violence in Guatemala, El Salvador and Honduras as the main cause of the crisis.

An internal border patrol memo, leaked to reporters, summarized interviews by agents on May 28 with 230 women and children apprehended in the Rio Grande Valley. It concluded that the primary reason for their arrivals in the United States was a perception that they would be permitted to remain in the country under the administration’s policies.

Another leaked memo from deputy border patrol chief Ronald Vitiello on May 30 estimated that more than 90,000 youths would be apprehended at the border this year and 142,000 next year, which are figures the administration had not made public.

“If the U.S. government fails to deliver adequate consequences to deter aliens from attempting to illegally enter the U.S., the result will be an even greater increase in the rate of recidivism and first-time illicit entries,” that memo said.

At a House Judiciary Committee hearing, Vitiello said the memo was prepared by his staff but never delivered to the interagency task force managing the emergency response. He told lawmakers that the situation had improved since Obama mobilized extra resources.

Border patrol agents have often complained about a lack of resources or other problems under recent presidents, including Obama.

Last year, the union representing agents at U.S. Immigration and Customs Enforcement worked closely with Republicans, including Sen. Jeff Sessions (Ala.), to lobby against a bipartisan comprehensive immigration bill approved by the Senate that would allow millions of undocumented immigrants a chance to earn citizenship.

ICE union officials said that field agents were constrained by administration guidelines that call for “prosecutorial discretion” when apprehending and deporting undocumented immigrants, focusing primarily on the most violent criminals.

The Senate passed its bill last June after Republicans added provisions to spend $35 billion on 20,000 new patrol agents and 350 miles of fencing along the Mexican border.

The tensions are rooted, in part, in long-standing morale problems within the Department of Homeland Security, a vast operation with 240,000 employees. Customs and Border Patrol was ranked 277th out of 300 federal agencies last year on a job-satisfaction survey; ICE ranked 291st.

Border agents have bemoaned recent budget cuts, including new limits on overtime pay, and have faced accusations of employing excessive force. A lawsuit filed this month by the American Civil Liberties Union on behalf of more than 100 children alleges they were abused while in the custody of border agents.

Homeland Security Secretary Jeh Johnson, who took over in December, said in a recent interview that morale problems relate largely to “basic pay and work environment issues.”

David Martin, a former DHS immigration lawyer who now teaches at the University of Virginia, said that concerns raised by border agents reflect a “very genuine and legitimate law enforcement and policy concern.”

“It’s a warning sign that somebody has to make hard decisions about what adjustments need to be done,” he said.