A nationwide crackdown to apprehend thousands of illegal immigrants across the country began late Saturday in the nation's largest city and several other places, according to an official.

Immigration and Customs Enforcement (ICE) resumed its previously announced plan to apprehend thousands of illegal immigrants who've been given orders to leave the country, targeting people in at least 10 cities. The ICE raids began late Saturday and into the early morning hours on Sunday in "a number of jurisdictions," not just New York City, a senior administration official confirmed to Fox News.

In an exclusive interview on "FOX & friends," Acting ICE Director Matt Albence said while he couldn't speak to anything specifically from an operational perspective, the overarching concern when the agency conducts any sort of enforcement operation is "the safety and security of both our officers that are conducting the operation as well as the public."

“We are doing targeted enforcement actions against specific individuals who have had their day in immigration court and have been ordered to be removed by an immigration judge,” Albence told Fox News’ Griff Jenkins. “We are merely executing those lawfully issued judge's orders.”

Albence, who said using the term raid does everyone "a disservice," added the agency is focusing on people who had had the opportunity to make an asylum claim in front of an immigration judge and chose not to do so or didn't appear for their first hearing. The acting director added that ICE gave those individuals the opportunity back in February to arrange for an orderly process to be removed from the country, but only 3 percent of people responded to letters that were sent out.

"At this point, we have no choice but to go out and execute those lawfully-issued removal orders from an immigration judge," he told "FOX & friends."

In addition to the enforcement operation, ICE also released a report on Sunday meant to illustrate the necessity for removing those who have committed crimes.

The first of what will be quarterly “Declined Detainer Reports” details incidents from the second quarter of fiscal year 2018, where law enforcement agencies arrested undocumented immigrants, ignored ICE requests to hold them until federal authorities could pick them up, and then those individuals were arrested on new charges. The report features highlighted cases, including ones where the arrests were for rape, murder, assault, burglary, car theft, drug possession, and DUI.

ICE RELEASES REPORT OF ILLEGAL IMMIGRANTS WHO ALLEGEDLY COMMITTED CRIMES AFTER COPS IGNORED DETENTION REQUESTS

In the cases described in the report, three of the individuals were eventually caught by ICE and removed from the U.S., one is believed to again be in law enforcement custody while ICE awaits action on a new detainer, and 12 are believed to still be at large.

In one such case, ICE said an illegal immigrant had been arrested and released 10 times by San Francisco police between February 2018 and January 2019, despite ICE issuing detainers. Each of those arrests included charges related to either burglary or a stolen vehicle.

"That individual is a one-man crime spree," Albence said on "FOX & friends."

The immigration sweeps were expected to start Sunday, but New York City Mayor Bill de Blasio said Saturday on Twitter that ICE agents had already taken action in New York. De Blasio said the raids in New York City took place in parts of Brooklyn and Manhattan.

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"Receiving reports of attempted but reportedly unsuccessful ICE enforcement actions in Sunset Park and Harlem," the mayor said. "@NYCImmigrants and advocates are connecting with residents and distributing resources door to door."

Advocates are coaching them on their rights, including instructions not to respond if agents knock on the door unless shown a warrant signed by a judge. The Democratic mayor has said his city would not cooperate with ICE.

Mark Morgan, acting commissioner of Customs and Border Protection, told "FOX & friends" on Sunday that the raids were about "enforcing and maintaining the integrity of the system."

"This is about the rule of law," Morgan said. "Those individuals who remain here illegally, especially those who've received due process more than any other nation in the world would provide someone that came here illegally, to including those with final orders, that there are consequences to those that remain here illegally. That's what today is about. "

Morgan, the former head of ICE, differed to disclose details about the raids. But he blasted mayors of cities who pushed back against the crackdown, calling their actions “unconscionable.”

"This is about going after individuals here illegally," he said. "Any city, any law enforcement agency that resists, does not cooperate, they're actually putting those cities in higher danger."

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On Friday, Albence said targets were on an "accelerated docket" of immigration court cases for predominantly Central Americans who recently arrived at the U.S. border in unprecedented numbers. Similar operations occurred in 2016 under President Obama and in 2017 under President Trump.

The operation will target people with final deportation orders on 10 major court dockets, including Chicago, Los Angeles, New York, and Miami. Albence said that doesn't mean arrests will be limited to certain areas. Authorities will go where their investigations lead, even if it's five states away from where the case is filed.

Trump said authorities were "focused on criminals as much as we can before we do anything else."

"It starts on Sunday and they're going to take people out and they're going to bring them back to their countries or they're going to take criminals out, put them in prison, or put them in prison in the countries they came from," the president said.

The Obama-era family operation in 2016 resulted in about 10 percent of those targeted being arrested, and the 2017 effort had a lower arrest rate, according to Albence.

Other operations that have targeted people with criminal arrest records have yielded arrests rates of about 30%, aided by access to law enforcement databases.

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Administration officials have said they are targeting about 2,000 people, which would yield about 200 arrests based on previous crackdowns.

Trump has said on Twitter that his agents plan to arrest millions of immigrants in the country illegally.

Fox News' Kevin Corke, Ronn Blitzer, Hollie McKay, Sam Dorman, and The Associated Press contributed to this report.