WASHINGTON—U.S. Citizenship and Immigration Services (USCIS), the federal agency charged with administering the immigration system, announced on Sept. 4 that it will hire armed special agents with the authority to investigate crimes and make arrests.

The service announced a final rule, which will be published on Sept. 5 in the Federal Register, that will authorize the appointment of special agents to carry firearms and operate as federal law enforcement officers to investigate fraud. This will allow Immigration and Customs Enforcement (ICE) to focus on disrupting transnational crime and capturing and deporting illegal immigrants, said the agency.

The rule is based on a delegation of authority, issued on May 2, from the secretary of homeland security that grants USCIS additional civil and criminal investigative powers, including ordering expedited removal. Previously, the service referred criminal matters to ICE’s Homeland Security Investigations division, which employs special agents.

“This historic moment will better address immigration crimes, hold those that perpetrate immigration fraud accountable, and act as a force multiplier for DHS and our federal law enforcement partners, including the Joint Terrorism Task Force,” wrote the service’s director, Joseph B. Edlow, in a statement.

“USCIS has always been an enforcement agency,” he noted.

The USCIS said that the service’s special agents will have authorities such as “making arrests, carrying firearms, executing search and arrest warrants, and other powers standard for federal law enforcement.”

Not all case officers at USCIS will become federal law enforcement officers—instead, only a select cadre within the service will be hired and granted these powers.

Some immigration advocates have criticized the move, saying that the USCIS’s armed component will intimidate otherwise eligible immigrants from seeking benefits from the service, such as petitioning for lawful permanent residency, such as a “green card,” or applying for naturalization as a U.S. citizen.

“Congress established USCIS after 9/11 to process legal immigration applications. Enforcement actions were left to other agencies to ensure that immigrants felt safe submitting their personal information and appearing for interviews,” wrote Jeff Joseph, the president of the American Immigration Lawyers Association, in a statement.

Allen Orr, former president of the association, alleged on social media that the change is unlawful.

“USCIS steps over the line when it conducts arrests & raids. The agency is violating the separation of authorities that Congress specifically enacted in §451 of the Homeland Security Act (2002),” Orr wrote.

USCIS Director Edlow told The Wall Street Journal that he is “not expecting this to have a chilling effect on applications.”

“I’m expecting this to have a chilling effect on fraudulent applications, and that’s what I want,” he said.

The Department of Homeland Security announced that the special agents will be classified as 1811 criminal investigators according to standard designations by the U.S. Office of Personnel Management for special agents of other agencies, like the FBI, Secret Service, Drug Enforcement Administration, Homeland Security Investigations, and Internal Revenue Service.

The basic qualifications for such a role involve possessing a valid state driver’s license, being between 21 and 37 years of age, and U.S. citizenship to obtain a security clearance.