Newark, New Jersey - A federal judge on Thursday ruled that the Department of Justice lacks the legal grounds to challenge so-called "sanctuary" immigration policies in four New Jersey cities.

Judge Evelyn Padin ruled against a lawsuit brought by the DOJ which accused four cities in New Jersey of having policies that unlawfully protect migrants.

The lawsuit was brought by DOJ lawyers in May, targeting the mayors and city council members of Newark, Jersey City, Hoboken, and Paterson. It accused them of impeding access to undocumented migrants.

According to the DOJ, the sanctuary city policies of all four localities represented "a frontal assault on the federal immigration laws and the federal authorities that administer them."

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Padin, however, pointed to the state's 2008 Immigrant Trust Directive (ITD), which defines how local law enforcement can engage and cooperate with federal immigration authorities, as the basis of a "fundamental flaw" in the DOJ's argument.

"It treats the challenged policies as though they operate in isolation. They do not," Padin wrote in the legal ruling. "The ITD is key to determining whether the Federal Government has Article III standing to sue."

"The Federal Government also lacks standing to sue for any alleged injuries that arise from restrictions found only in the challenged policies because it does not identify any concrete injury caused by those provisions."

She dismissed the lawsuit without prejudice, which means it can be refiled at a future date.

The DOJ has yet to respond to the ruling, but Jersey City Mayor James Solomon celebrated on social media, writing: "I will never stop fighting to protect Jersey City's immigrant communities."

"Today's ruling renews my fight against Trump's cruel and abusive overreach," he continued. "40% of Jersey City residents were born in another country, and this diversity is what makes our communities stronger and more vibrant."