New York City’s municipal ID card program, launched to get immigrants out of the shadows, was enacted in 2014 with a provision promising to safeguard undocumented immigrants by destroying the identifying documents associated with their card applications.

A Republican-led legislative and congressional fight is now brewing over whether the documents should be destroyed after two years, as the law provides—or handed over to immigration officials. The documents include copies of birth certificates, foreign driver’s licenses, U.S. visas, and passports.

Two congressional committees this week are reviewing a GOP-led lawsuit filed in December to stop the destruction of the records. Officials with the Senate Homeland Security’s Subcommittee on Investigations and the House Committee on Homeland Security told the New York Post they’re discussing whether to investigate the record-destruction provision.

Meanwhile, New York state Sen. Terrence Murphy (R-Westchester and Hudson Valley) introduced legislation to require the city to turn over the documents to the New York State Division of Homeland Security and Emergency Services and the New York State Office for New Americans within ten days of receiving an application. The bill imposes a $1,000 civil penalty for each application or document that is destroyed.

Murphy told the New York Post that the records destruction was “an effort to evade the enforcement of federal immigration laws.”

The controversy is emblematic of a larger battle, as undocumented immigrants nationwide fear that personal identifying records associated with driver’s licenses and ID cards will be used to find and deport them. President Trump has vowed to deport millions of undocumented immigrants.

New York City Mayor Bill de Blasio, a Democrat, championed the ID cards and the provision in the ID cards program that protects undocumented immigrants by destroying the records associated with their applications.

About 900,000 New Yorkers have been issued the ID cards, which allow residents to open accounts at some banks and access city services regardless of their immigration status, according to the Post. Although the city doesn’t ask for the residency status of municipal ID holders, an estimated 500,000 undocumented immigrants live in New York City.

De Blasio’s office said last month that the city would not hold any documents associated with an application for a city ID card, as the Post reported.

Raising the specter of crimes committed by immigrants is a favorite among Republican legislators targeting undocumented immigrants. But research cited by the conservative Cato Institute indicates that immigrants commit fewer crimes than U.S.-born residents.

“Rather than side with xenophobia, the mayor will side with our police commissioner and counter-terror chief who have both said the card makes our city safer,” mayoral spokesperson Rosemary Boeglin said.