Oct. 12 (UPI) — The Justice Department on Thursday sent out a “last chance” warning for several U.S. cities to comply with federal immigration laws, the latest step in a battle over so-called “sanctuary cities.”

The Justice Department has threatened to cut off federal funding to boost law enforcement in cities that do not comply with the Department of Homeland Security’s efforts to identify and deport undocumented immigrants.

The cities cited by the Justice Department were New York, Chicago and surrounding Cook County, Ill., New Orleans and Philadelphia. Those cities were given a deadline of Oct. 27 to provide the Justice Department with documentation proving their existing laws and law enforcement practices are in line with federal immigration policy.

Two other jurisdictions, the state of Connecticut and Milwaukee County, Wis., heeded Justice Department warnings and reversed policies meant to shield undocumented immigrants from possible deportation. Additionally, the Justice Department said subsequent investigations found Miami-Dade County, Fla., and Clark County, Nev., where Las Vegas is located, were already in accordance with federal immigration law, though previously they had been listed otherwise.

Several U.S. cities and counties passed local laws or enacted procedures that prohibit law enforcement from notifying Homeland Security when an undocumented immigrant is identified or arrested. Critics have dubbed such places “sanctuary cities.” Proponents have argued that enlisting street-level police to enforce national immigration policy makes it harder for them to investigate and stop crimes, because undocumented immigrants won’t cooperate if they think they will be deported.

A federal law known by the shorthand 1373 requires local police to detain anyone suspected of being in the country illegally for several days until investigators from Immigration and Customs Enforcement can intervene, even if the crime they’re accused of is minor, or no charges are filed.

Critics have also pointed out local compliance with 1373 can lead to jail overcrowding.

The Trump administration has said enforcing immigration law is vital to national security and crime reduction.

“Jurisdictions that adopt so-called ‘sanctuary policies’ also adopt the view that the protection of criminal aliens is more important than the protection of law-abiding citizens and of the rule of law,” Attorney General Jeff Sessions said in a statement. “… I urge all jurisdictions found to be out of compliance in this preliminary review to reconsider their policies that undermine the safety of their residents. We urge jurisdictions to not only comply with Section 1373 but to establish sensible and effective partnerships to properly process criminal aliens.”