Prototypes of border walls in San Diego, on display last year. Federal Judge Gonzalo P. Curiel was berated by Donald Trump for his handling of lawsuits alleging fraud at now-defunct Trump University. Curiel heard arguments Friday in a lawsuit that could block construction of a border wall along the Mexican border or at least cause major delays. (Elliott Spagat/AP)

The federal judge whom President Trump characterized during his campaign as “a Mexican” and therefore biased against him said he would announce a ruling next week that could determine whether the government can proceed with its expedited plans to build a border wall.

District Judge Gonzalo P. Curiel is presiding over a lawsuit filed by advocacy groups and the state of California challenging the Department of Homeland Security’s plans to bypass standard environmental-impact studies and rapidly expand barriers along the Mexican border.

Curiel said Friday that DHS has yet to explain why it must proceed so urgently in its construction plans.

“By waiving environmental protections, we are ignoring something that has been very important to Congress for the past 40, 50 years,” the judge told government attorneys. He asked them to provide more information by Tuesday and said he would issue his ruling soon after.

Galen N. Thorp, a government attorney representing the Department of Homeland Security, said DHS’s plans were consistent with congressional authorizations.

“This case is about plaintiffs’ opposition to Congress’s decision that border infrastructure can, in certain circumstances, be a higher priority” than environmental laws, Thorp said.

Plaintiffs in the suit argue that environmental waivers granted by Congress a decade ago involving matters of crucial border security cannot be applied to future wall construction. A ruling against DHS would likely delay the Trump administration’s plans to move rapidly if Congress provides billions in funding for the wall.

The plaintiffs said they are not challenging the government’s right to replace or maintain existing barriers, only “the projects they want to do now,” said Michael Cayaban, an attorney for the state of California.

Curiel was the judge in an unrelated class-action lawsuit against the president’s now-defunct Trump University, and the judge’s alleged bias against Trump became a running theme during his presidential campaign.

At a rally here in May 2016 that triggered protests, Trump blasted Curiel as “a hater of Donald Trump,” then continued to lash out after the judge ordered the release of internal Trump University documents related to the suit requested by The Washington Post.

Trump told supporters at the time that Curiel harbored a bias against the candidate’s plans for a border wall because the judge was “Spanish” and “a Mexican.”

Curiel’s parents were immigrants from Mexico. He was born in Indiana.

“Look, he’s proud of his heritage, okay?” Trump said of Curiel in a June 2016 interview with CNN. “He’s a Mexican. We’re building a wall between here and Mexico.”

Trump’s remarks were widely condemned at the time, but Curiel did not respond publicly. Trump agreed to pay $25 million to settle the fraud claims in March, soon after moving into the White House.

Brian Segee, the lead attorney for the Arizona-based Center for Biological Diversity, a plaintiff in the suit, said his group is challenging DHS’s attempt to bypass standard procedure.

“Did Congress intend, as we argue, to limit the unprecedented and sweeping authority of the DHS secretary to do away with laws at will?” Segee said in an interview Friday. “Was that limited to specific fencing projects that have already been completed? Or was it perpetual authority that can be invoked now, or 10 years or 20 years from now?”

Trump is seeking $25 billion for enhanced border security, including hundreds of miles of new barrier construction. About one-third of the 2,000-mile border with Mexico has some form of wall or fencing, and the president’s proposal would extend the structure by about 300 miles, while replacing another 400 miles with more formidable barriers.

DHS is evaluating eight wall prototypes that are on exhibit outside San Diego, and each one is taller and more elaborate than almost anything currently in place.

Environmental groups suing the government say additional barriers will harm wildlife by cutting off their natural migration routes or access to the waters of the Rio Grande.

Stretching from the southern Rockies to the Gulf of Mexico, the river spans nearly two-thirds of the U.S.-Mexico boundary, passing through arid mountain regions and deserts where it is a vital water source for farmers, ranchers and wildlife. Large fauna cross the border in other remote areas where the international boundary is little more than a line on a map.

“The wall could preclude the movement of endangered species or other animals, like the jaguar, that move back and forth, leading to their potential extirpation in the United States,” Segee said.

New wall construction is likely to happen first on federally protected lands, including parks and wildlife sanctuaries because the government already owns the property.

The president’s wall-building blueprints also call for thousands of miles of new roadways along the border to provide access for maintenance crews and law enforcement.

Miroff reported from Washington.