Undocumented immigrants who have entered the U.S. since last year face more scrutiny than many criminals,

According to the Boston Globe, U.S. Immigration and Customs Enforcement (ICE), the second largest criminal investigative agency of the federal government's U.S. Department of Homeland Security, is subjecting many of the newest arrivals to 24-hour surveillance that includes GPS ankle bracelets.

The monitoring system, which immigration officials stated is cheaper than detention, could dramatically expand next year, the newspaper noted.

Veronica Morales, a Guatemalan woman who lives in Lynn, Massachusetts, is required to wait for hours at her home each Thursday in case an immigration contractor drops by, the Boston Globe detailed. "We're not criminals," the 21-year-old said. "Why are they watching us?"

ICE defended its Alternatives to Detention (ATD) practice, pointing out that the program is only for adults and that its implementation varies on a case-by-case basis.

"The ATD program is used to increase compliance with release conditions, court appearances and final orders of removal while allowing participants to remain in their community as they move through immigration proceedings," ICE spokeswoman Jennifer Elzea explained.

David Inserra, a homeland-security expert at the conservative Heritage Foundation think tank, agreed that GPS tracking anklets make for a "robust" alternative to arrest, the Daily Signal noted.

The ATD methods "are cost-effective ways to ensure that illegal immigrants show up at court hearings," Inserra argued. "With that being said, some individuals need to be detained and criminal aliens fit that bill. While the use of proven and strong ATD should expand, the administration should also be filling its detention beds, as is required by law, rather than allowing known criminal aliens to be released."

Immigration-rights advocates, however, expressed concern that ICE is expanding both its monitoring system while also adding beds to its detention centers, the Boston Globe noted.

"Rather than an alternative form of detention, it's an alternative form of profit for the (private) company that runs the program," Detention Watch Network Policy Director Mary Small told the newspaper.

And Hans Bremer, a Providence immigration lawyer who says he has dozens of clients in the intensive-monitoring program, called the current extent of ATD "ridiculous."

"I assume every single woman that comes to my office will be on a GPS device," Bremer said. "It's grown exponentially."