In a letter to Mayor Kenney this week, Department of Justice officials said that they have concluded Philadelphia's sanctuary policies violate federal law, giving the city two weeks to argue the decision or risk losing federal grant money.
Landrieu and other city officials have repeatedly denied that New Orleans is a "sanctuary city" and have contested previous findings by Sessions' Justice Department with letters certifying that the NOPD is in compliance with federal law.
The cities cited by the Justice Department were New York, Chicago and surrounding Cook County, Ill., New Orleans and Philadelphia.
"New York City has hit on the right approach to make this the safest big city in the country: welcome immigrant communities to build trust and cooperation with local law enforcement", De Blasio has said. Critics have dubbed such places "sanctuary cities".
"This letter is to inform you that, based on a preliminary review, the Department has determined that your jurisdiction appears to have laws, policies, or practices that violate" that section of law, Acting Assistant Attorney General Alan Hanson wrote to Mayor's Office of Criminal Justice director Elizabeth Glazer.
Millions of dollars in federal money are at stake if those jurisdictions can not prove they are abiding by federal immigration laws.More news: Razer : a smartphone unveiled on November 1, 2017 ?
Critics have also pointed out local compliance with 1373 can lead to jail overcrowding.
U.S. Attorney General Jeff Sessions said in a statement that these cities "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". U.S.C. 1373 - states that a federal, state or local government entity can not restrict any government entity from "sending to, or receiving from, the Immigration and Naturalization Service information regarding the citizenship or immigration status, lawful or unlawful, of any individual".
Landry, in a press release Thursday, declared himself "the state's most aggressive critic of sanctuary cities" and said he'd repeatedly warned Landrieu over the policies.
The exchange between Landrieu and Sessions' Justice Department is hardly the first contentious battle over the NOPD's policies on immigration. "Mitch Landrieu is playing politics at the expense of New Orleans", Landry said in a statement.
The Justice Department review brought better news for others. The pair have threatened to cut off federal funding to the cities - which include Hartford and New Haven - but so far that hasn't happened.
Although city officials stop short of calling New Orleans a "sanctuary city", New Orleans has been included on a list of such jurisdictions because of its policy towards Immigration and Customs Enforcement (ICE).
Attorney General Jeff Sessions argued it was wrong to apply an order nationally in a case brought by Chicago and that it should only apply to that city.