The Department of Homeland Security announced Tuesday a new registry for unauthorized immigrants living in the United States.

A statement on the DHS website says the registry is required for people over 14 years old that have entered the United States illegally and warns that failure to register could lead to fines or criminal prosecution.

The requirement has long been asked of immigrant illegally in the country, stemming from the Alien Registration Act of 1940. In defense of the registry, DHS cited the Immigration and Nationality Act of 1952, which codified the registration requirement.

"The administration is returning to an authority that has been on the books, and that is the law for a long period of time," said Michelle Mittelstadt, communications director for the Migrant Policy Institute. "This has been a law that's been on the books going back decades now, going back to the 1950s. It hasn't been actually implemented since the 1960s."

"For decades this law has been ignored – not anymore," DHS said in its statement.

While unauthorized immigrants in the US have had to register with the federal government, this requirement hasn't been enforced, immigration experts say. But the move comes amid a slew of policies aligned with President Donald Trump's campaign promise to crack down on illegal immigration.

"I think the Trump administration would tell you that they're using all existing authorities to go after the unauthorized population, and in particular, also to kind of turn up the pressure and encourage people to self-deport," Mittelstadt said.

The DHS announcement followed an ad campaign featuring Secretary Kristi Noem who appears alongside immigration enforcement. Noem posted on X warning undocumented people "to leave our country NOW" and those that enter unlawfully "will be hunted down and deported."

"It's going to cause a lot of fear, and there are significant portions of the unauthorized population that are exempt from this registry and that might not be aware of it," said Mittelstadt.

The registration policy does not apply to people who entered the United States legally and overstayed their visas, people with work visas, residency, a temporary protective status or humanitarian parole.

Only people who have entered the country illegally are required to register.

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This policy also comes as federal immigration officials are quickly rolling out agreements with local and state law enforcement to create on the ground "task forces."

Florida became the first state to sign an agreement.

Florida Governor Ron DeSantis boasted that Florida has the strongest immigration policies in the country after passing new legislation and signing the agreement.

Kansas Attorney General Kris Kobach said in a press release the state is the second state to "deputize state law enforcement to enforce immigration laws under Trump."

Oklahoma Department of Public Safety Commissioner, Tim Tipton, announced Tuesday an agreement between ICE and the state's police force. Tipton said training is anticipated to begin next week.

Idaho and Texas have also signed agreements.

The U.S. Citizenship and Immigration Services website details the rules of the new registration and said it would create a form and process soon.