The undocumented immigrants handed photo IDs and wrinkled tax records to volunteers in the windowless office, who tapped their earnings into calculators and delivered the news:

The day laborer owed $600 in state and federal taxes. The maid, $1,130. And the house painter, a whopping $6,000.

“That’s rough,” Salvador, a 44-year-old house painter from Guatemala, said in Spanish, blinking in shock at his hefty tax bill. “But we have to pay.”

For immigrants from Guatemala, El Salvador and other nations who are in this country illegally, filing tax returns is an act of faith they hope will benefit them if Congress lets them apply for legal residency in the United States. But in the first tax season under President Trump — who has vowed to crack down on illegal immigrants in part, he says, because of a belief that they drain government resources — the ritual is unfolding in an atmosphere of increased urgency and fear.

“It’s a myth that people who are undocumented don’t pay taxes,” said Cathryn Ann Paul, as she helped immigrants fill out tax forms at CASA de Maryland, a nonprofit group in Langley Park. “Every time I see that on the news, it makes me cringe.”

Federal law requires all workers to file income tax returns, even immigrants in the United States illegally. Since 1996, those who do not have a Social Security number can get a nine-digit Individual Taxpayer Identification Number (ITIN) from the Internal Revenue Service.

More than 4 million people a year file using ITINs, according to federal records. The figure nearly doubled in the past decade, as Congress mulled legislation that would have created a path to citizenship for 11 million illegal immigrants, as long as they paid back taxes. Maryland, one of 12 states that issues limited driver’s licenses to undocumented immigrants, will not do so unless those immigrants show proof that they have filed tax returns.

Some taxpayers who file this way are legal immigrants and foreign investors who do not have Social Security numbers. But most are undocumented immigrants eager to secure a foothold in a nation that does not otherwise embrace them, establishing proof of residency and documenting their incomes. Like legal residents and U.S. citizens, they also want to know whether they qualify for a refund.

This tax season, advocates say, immigrants are so rattled by Trump’s pledge to accelerate deportations that some are afraid to file returns, worried that addresses and other personal information on their returns could end up with federal agencies administering the crackdown. Adding to their stress is a law that took effect this year that is forcing hundreds of thousands of people to reapply for their ITINs.

Maryland Comptroller Peter Franchot has visited CASA workshops to reassure undocumented immigrants that his office, which processes state returns, will not share their private tax information with Immigration and Customs Enforcement.

“Good God, no, and I never will,” Franchot (D) said in a telephone interview. “If I have to get my law enforcement division to stand outside the door in Annapolis, I will.”

The IRS echoed that sentiment this week, saying tax information cannot be shared with another government agency unless authorized by law. “The IRS has strong processes in place to protect the confidentiality of taxpayer information, and this includes information related to tax returns filed using ITINs,” a statement from the agency said. “There is no authorization under this provision to share tax data with ICE.”

About half of undocumented immigrants file personal tax returns, channeling $1.1 billion to state coffers, according to the Institute on Taxation and Economic Policy. The IRS could not say how much ITIN filers paid in income taxes last year, but past federal reports have estimated that they pay billions of dollars in federal taxes over the past decade.

Critics of illegal immigration worry that undocumented immigrants are increasingly filing returns to take advantage of tax credits and other benefits that, they say, should be reserved for low-income families here legally. Some states, voicing concerns about fraud, have refused to issue refunds to people who file with taxpayer-identification numbers unless they provide additional proof of identity.

“The reason that they’re filing is to not pay income tax, but to get a cash welfare program benefit out of the government,” said Robert Rector, a senior research fellow at the Heritage Foundation, a conservative think tank based in Washington. “They do pay taxes, but they’re getting much more in benefits than they pay out in taxes.”

Advocates for undocumented immigrants counter that they are generally ineligible for most tax breaks. Many support relatives back home, for example, whom they cannot claim as dependents. Meanwhile, undocumented immigrants pay into programs such as Social Security, even though they cannot collect that money.

“Immigrants paying taxes shouldn’t be a controversial issue,” said Jackie Vimo, policy analyst at the National Immigration Law Center, a nonprofit organization that advocates for low-income immigrants and their families. “It brings money into the economy.”

Federal records show that most taxpayers receive refunds, whether they are here legally or not. But on Wednesday, the half-dozen undocumented immigrants who crammed into a small basement office at CASA had to pay.

Some were self-employed and some were paid in cash and had not withheld enough in taxes, leaving them owing Uncle Sam at the end of the year. Most earned less than $11,000 annually. None had health insurance. And although they said they themselves did not fear the IRS, some declined to give their last names because they worry about deportation.

Hermenegildo Alvizurez, a graying day laborer who came here from Guatemala in 2008, was stunned that he had to pay $600 in taxes. He does odd jobs two or three days a week and sends money home to his five children.

“Where am I going to get that kind of money?” Alvizurez, 56, said in Spanish.

Maria, a 30-year-old maid from El Salvador, said she would have to set up a payment plan to settle her $1,130 state and federal tax debt. “I came here to help my family,” the Silver Spring resident said. “I don’t have a lot of money.”

Eladia, a 50-year-old mother of four from Guatemala, said she has filed taxes every year since she crossed the border illegally in 1998. For 19 years, she said, she has lived in the same Bladensburg apartment, worked for the same cleaning company and never otherwise broken the law. She owes the state and federal government more than $1,200.

“How strange, not even the state is going to give me anything?” she asked, as volunteer Philip Webre, a retired analyst for the Congressional Budget Office, pored over her records. Webre shook his head, and she sighed.

“I’m not going to receive anything,” she said, “But I’m happy because I declared my taxes.”