The changes were aimed at enabling the U.S. to more quickly reject people's asylum claims, allowing for quicker deportations. Administration officials said the goal was to deter people from trying.
Now, if migrants pass through a country on the way to the United States and don't apply for asylum there, then they are ineligible to seek asylum in the United States, according to the rule.
In a statement, Attorney General William Barr insisted most asylum seekers have merit-less claims -- an assertion that immigration advocates say is not true.
"The United States is a generous country but is being completely overwhelmed by the burdens associated with apprehending and processing hundreds of thousands of aliens along the southern border," Barr said.
According to a rule posted on the Federal Register, the department concluded that people who come from northern triangle countries such as Guatemala, El Salvador and Honduras initially have to apply for asylum in the country that they first pass through before applying for asylum in the United States.
This rule also applies to children who attempt to cross the U.S. Mexico border without a legal guardian.
Often times, migrants pass through Mexico on the way to the United States. Last month, 85% of migrants who attempted to cross the border illegally came from a country other than Mexico, according to Customs and Border Protection data.
The Department of Justice is calling it a "new mandatory bar" that asylum seekers have to meet.
However, it appears to be inconsistent with federal law, said John Cohen, a former acting undersecretary at the Department of Homeland Security and ABC News contributor.
"The Trump administration is trying to unilaterally reverse our country's legal and moral commitment to protect those fleeing danger," Lee Gelernt, deputy director of the Immigrants’ Rights Project of the American Civil Liberties Union, said in a statement. "This new rule is patently unlawful and we will sue swiftly."
President Donald Trump and the president of Guatemala were expected to sign an agreement on Monday requiring migrants who travel through Guatemala to claim asylum there, rather than the U.S. But that meeting was postponed.
A senior administration official told ABC News that the meeting is being "rescheduled" and adds that "the United States will continue to work with the Government of Guatemala on concrete and immediate steps that can be taken to address the ongoing migration crisis."