U.S. Department of Homeland Security Secretary Kristi Noem was in Gary, Indiana, on Thursday to announce the arrests of hundreds of immigrants, many of them accused of driving trucks without a valid license.

Noem also answered questions about "Operation Midway Blitz," the Trump administration's ongoing immigration enforcement operation in the Chicago area.

Noem held a news conference with several other officials including Indiana Governor Mike Braun, U.S. Department of Transportation Secretary Sean Duffy, and U.S. Immigration and Customs Enforcement Director Todd Lyons. The mayor of Gary said he would not attend. 

Noem said federal immigration authorities, working with Indiana State Police troopers, have arrested 223 suspected unauthorized immigrants on state highways, including 146 truck drivers, as part of the operation.  

"If you are here driving on our streets illegally and our highways, you are endangering our citizens, and your days are numbered," she said.

According to Homeland Security, approximately 3,000 arrests overall have been made since "Operation Midway Blitz" began in September.

Aside from the arrests that were announced in Gary, and about 100 other arrests announced in press releases from Homeland Security, U.S. Immigration and Customs Enforcement, and U.S. Customs and Border Protection, CBS News Chicago wanted to know who the remaining people who have been arrested are.

"We can get that for you. Those are individuals that have been detained, that we've interacted with, that were here illegally, committed crimes, or had final orders of removal issued against them," Noem said.

In a separate press conference in Illinois, Gov. JB Pritzker asked Homeland Security to halt immigration enforcement efforts under Operation Midway Blitz for Halloween.

"I've sent a letter to Kristi Noem and to the Department of Homeland Security leadership, asking them to pause all of their federal agent operations for the entirety of the Halloween weekend," Pritzker said.

Pritzker's request came after federal agents deployed tear gas in the Old Irving Park neighborhood last weekend as kids were making their way to a Halloween parade.

"I'm asking for basic human decency. I think their response will be revealing," he said.

Noem flatly denied Pritzker's request.

"No, we're absolutely not willing to put on pause any work that we will do to keep communities safe. The fact that Governor Pritzker is asking for that is shameful," she said.

Noem was also asked how "Operation Midway Blitz" is expected to continue, but Noem would not offer a deadline for the operation.