Despite resistance from city and state officials, a controversial immigration enforcement program will begin operation today in Connecticut.

Secure Communities, a U.S. Immigration and Customs Enforcement program, will begin checking fingerprints of suspected criminals submitted by local police to the FBI against ICE databases in an effort to deport criminals residing in the country illegally. While Gov. Dannel Malloy’s office issued a statement Monday that criticized Secure Communities, New Haven officials said they are still waiting to see to what degree the state cooperates with the federal program.

Through Secure Communities, when ICE officials have reason to believe a suspect may be undocumented, they can issue a detainment request to the state, allowing the suspect to be held for up to 48 hours, during which immigration officials decide whether to initiate deportation proceedings against the suspect. While the program’s stated mission is to prioritize illegal immigrants who have committed crimes for deportation action, critics of the program, including local officials such as Mayor John DeStefano Jr. and New Haven Police Department Chief Dean Esserman, argue that in practice it deports undocumented residents who have a minor or nonexistent criminal record, in addition to having damaging collateral consequences for local law enforcement.

In Monday’s statement, Mike Lawlor, the state’s undersecretary for criminal justice policy and planning, said Malloy has ordered Department of Corrections Commissioner Leo Arnone to review the program, and said the state would decide whether to honor ICE’s detainment requests on a case-by-case basis.

“We still have yet to see a specific policy from the state regarding how it will handle detainers issued as a result of Secure Communities,” City Hall spokeswoman Elizabeth Benton ’04 said. “We are looking forward to seeing the policy.”

In a Tuesday email, Lawlor said some jurisdictions choose to ignore every detainment request from ICE while others decide not to honor a portion of the federal requests. Connecticut, he said, will fall in the latter category.

A 2011 review of Secure Communities by the Department of Homeland Security found that “the impact of Secure Communities” extended beyond dangerous offenders. A Yale Law School study of Secure Communities in Fairfield County, where it has been active since 2010, found that 71 percent of those deported through the program were not violent or multiple offenders.

DeStefano and several city and state officials held a press conference at City Hall Monday calling on ICE to delay implementation of the program, which is currently active in 30 states, and asked Malloy to distinguish between serious and low-level offenders in handling detainment requests.

Benton repeated some of the criticism leveled at Secure Communities.

“Secure Communities is a misguided and mishandled program that will neither make New Haven more secure nor a stronger community,” Benton said. “Conversely, Secure Communities will harm community policing efforts in New Haven to build trust between immigrant communities and the police department.”

ICE spokesperson Ross Feinstein declined to respond to questions Tuesday, but instead issued a statement that announced a training program — to be run by the Department of Homeland Security’s Office for Civil Rights and Civil Liberties — that will train local law enforcement agencies on how to provide more information about Secure Communities to the public. Feinstein’s statement emphasizes that Secure Communities prioritizes the deportation of criminals.

“Approximately 94 percent of the total Secure Communities removals fall within ICE’s civil enforcement priorities, including convicted criminals, recent illegal border entrants and those who game the immigration system,” the statement said.

Lt. Paul Vance, a spokesperson for the Connecticut State Police, said Tuesday that he was unaware of the program’s impending implementation in the state and had not been notified by ICE that the program would begin. Neither were top New Haven officials, including DeStefano and Esserman.

Benton said city officials learned that Secure Communities would begin in Connecticut through secondhand sources, although she added that an email may have been sent to former NHPD Chief Frank Limon, who left New Haven last fall.

Fairfield Police Department Chief Gary MacNamara said the program has not changed the way his department works. Since his officers already submit fingerprints to the FBI, Secure Communities operates in the background and only “piggybacks” off their arrests, he said.

“We haven’t become immigration officers,” MacNamara said. “We aren’t out looking for immigrants. We just do our job the way we always did it.”

MacNamara said he has seen no difference in relations between Hispanics and police officers, but he added that “every community is different.”

“We need the community support to do our job, so if there were concerns in our community, we would certainly want to explain ourselves better,” he added.

Secure Communities began under the Bush administration in 2008 and will become mandatory nationwide by 2013.