The Department of Homeland Security says it has issued more than 103,000 civil fines totaling about $84 billion to illegal immigrants since President Donald Trump's second term in office began, while collecting more than $1 billion in payments as part of the president's immigration enforcement agenda.

Under the policy, illegal immigrants subject to final removal orders who fail to voluntarily leave the United States can be fined $998 per day until they comply with their removal orders, reports the New York Post on Wednesday. 

DHS said immigrants must pay the penalties before they are deported and warned that assets may be seized from those who fail to pay.

The fines are part of a broader administration effort to encourage illegal immigrants to leave the country voluntarily rather than face arrest and removal. DHS has argued the program is less expensive than traditional deportation proceedings and provides an incentive for migrants to self-deport.

U.S. Customs and Border Protection has promoted the policy through its CBP Home app, which allows migrants to notify the government of their plans to depart the United States.

A CBP flyer tells migrants that "self-deportation is safe" and encourages them to "leave on your own terms by picking your departure flight."

According to DHS, illegal immigrants who voluntarily leave the country and are not convicted criminals may be allowed to keep money earned while in the United States and preserve eligibility to seek legal immigration status in the future.

Some also may qualify for government-subsidized travel if they cannot afford airfare home.

The agency warned that those who refuse to self-deport face apprehension by immigration authorities "with no opportunity to get your affairs in order beforehand."

DHS has said more than 3 million illegal immigrants left the United States during Trump's first year back in office, including an estimated 2.2 million who self-deported. As of May 17, the department also reported deporting nearly 900,000 illegal immigrants and arresting more than 900,000 others.

The administration has credited the enforcement campaign with reducing illegal immigration following record border crossings during former President Joe Biden's administration.

The Trump administration has defended the policy as a lawful enforcement tool aimed at encouraging compliance with final removal orders and reducing the costs associated with immigration enforcement.

The civil fines, however, have drawn criticism from Senate Democrats.

Sen. Alex Padilla of California, the ranking member of the Senate Judiciary Committee's Immigration Subcommittee, and Senate Democratic Whip Dick Durbin of Illinois sent a letter this week to Acting Attorney General Todd Blanche and DHS Secretary Markwayne Mullin urging the administration to halt what they called the improper use of civil penalties.

The senators said some fines have been issued to immigrants who have legal authorization to remain in the United States, including Deferred Action for Childhood Arrivals recipients, green card applicants, and survivors of domestic violence or human trafficking with pending immigration cases.

"In assessing these fines, your Departments appear to have abandoned critical safeguards that have long prevented law-abiding immigrants from being improperly targeted with unreasonable penalties," the senators wrote, arguing the administration had weakened procedural protections while expanding use of the fines.