U.S. Immigration and Customs Enforcement is talking up 29 Chicago-area arrests that were part of a national operation targeting transnational gangs.

Gary Hartwig, special agent in charge of ICE’s Chicago-area Homeland Security Investigations, said the operation began April 9 and lasted three days. He said police in Wheeling, Waukegan, Joliet and Elgin took part.

“I don’t have the time and resources to just go round up everybody who happens to be in the country illegally,” Hartwig said. “Our job is to focus our resources on criminal gangs and criminal organizations — in this case, transnational gangs — who are operating in our communities and making our streets unsafe.”

As a result of the Chicago-area arrests, ICE says, a 26-year-old U.S. citizen and two foreign nationals face criminal charges. Officials say the other 26 detainees are in deportation proceedings.

An ICE statement says the operation, dubbed Project Nefarious, led to more than 600 arrrests nationwide. The statement says the operation spanned 150 U.S. cities and reached Honduras. The operation’s impetus, the agency adds, was a 2011 federal report that identified gangs tied to human smuggling and trafficking.

The victims of those crimes include foreign nationals in the United States, but some immigrant advocates are withholding praise for the operation.

“We support ICE’s efforts to target criminal enterprises rather than immigrants whose only crime is working to support their families,” said Chuck Roth, litigation director of the Chicago-based National Immigrant Justice Center. “But past ICE actions have usually turned out to involve more arrests of bystanders and family members than of individuals actively engaged in wrongdoing.”