Attorney General Jeff Sessions has not slowed down in his tough on immigration approach but faces a tough challenge in cities that have adopted sanctuary policies, meaning they don't fully cooperate federal immigration law.

The Justice Department told eight of these cities that they have until June 30 to show they are in compliance with Statute 1373, a federal statute that prohibits local and state governments and agencies from enacting laws or policies that limit communication with Immigration and Customs Enforcement or Customs and Border Protection about "information regarding the immigration or citizenship status" of individuals.

Mayors of those cities, and others that have adopted so-called sanctuary city policies, continue to declare openly that they actually are in compliance. Sessions says they are not.

According to Seth Stodder, who was assistant secretary of homeland security for border, immigration and trade policy under former President Barack Obama, Sessions is "stuck legally" for what more he can do in terms of undercutting sanctuary city policies.

"The problem with 1373 is that is extraordinarily narrow," Stodder told the Washington Examiner. "Local authorities can say, 'We don't have the information to tell you,'" about someone's immigration status.

For example, in Los Angeles, Stodder said, law enforcement authorities do not ask someone their immigration status. So if they don't know an immigration status, they can say they aren't restricting communications with the federal government because they don't have anything to reveal.

"It's like don't ask don't tell," he explained.

But for Dan Stein, president of the Federation for American Immigration Reform, cities that refuse to honor ICE laws "are attacking the enforceability of immigration laws itself."

Stein told the Washington Examiner that leaders of sanctuary cities are "trying to make fine distinctions [with 1373] to protect themselves."

"I see a political confrontation emerging," Stein said. "Sessions has a whole range of tools available," to fight against sanctuary policies, he explained, adding, "It begins with an attitudinal shift based on the bully pulpit."

Jessica Vaughan, the director of policy studies at the Center for Immigration Studies, told the Washington Examiner that these mayors "may be somewhat in a state of denial on their compliance with the federal law on sanctuary policies."

"If they do not allow officers to freely communicate with ICE, or if they block ICE from access to jails, or if they have a policy that deliberately hinders ICE by ignoring all ICE detainers and requests for information about a criminal alien could well be, and probably are, violations of 8 USC 1373," she said, adding, "My experience in reviewing these policies and talking with these sanctuary politicians is that they have interpreted section 1373 very strictly and swear they are following it."

Vaughan says she hopes the DOJ will take the sanctuary city battle to the court.

"Another option that DOJ is working on, which we support, is to address some of the lawsuits that have occurred by defending the federal government's authority to enforce immigration laws, and the tools that are needed to do it, like detention," she said. "In addition, the DOJ should seek an injunction against some of the more egregious sanctuary policies, such as in Philadelphia or New York, if they continue them even after losing funding."

Vaughan also said the DOJ could prosecute local officials "responsible for policies that result in the release of criminal aliens who go on to cause harm after their release."

Sessions is stuck however for right now until June 30, when he will receive letters of compliance from eight specific cities. Then, he can decide if their claims of compliance are up to what he wants, Stodder said.

Until then, he may just continue his overarching tough-on-immigration rhetoric through other means.

Stodder did point out the irony in what Sessions is doing, from a conservative point of view.

Sessions has repeatedly said he will no longer sign consent decrees — i.e. court binding agreements for police reform — because state and local law enforcement does not need to be interfered with by the federal government.

"So then why doesn't Sessions trust someone like the LAPD chief if he is saying changing their sanctuary policies will make the city less safe?" Stodder asked.