FIRST ON FOX – The Department of Justice demanded California’s public high schools confirm by next week that they do not allow transgender athletes to compete in girls’ sports, escalating a federal inquiry into the state over its compliance with Title IX.

Assistant Attorney General Harmeet Dhillon, who heads the DOJ Civil Rights Division, said in a letter obtained by Fox News Digital that public school districts must "certify in writing" by June 9 that they will not abide by the the California Interscholastic Federation’s gender identity rules.

"Knowingly depriving female students of athletic opportunities and benefits on the basis of their sex would constitute unconstitutional sex discrimination under the Equal Protection Clause," Dhillon warned in the letter, obtained by Fox News Digital. 

CALIFORNIA HIGH SCHOOLER BEGS STATE OFFICIALS TO BAN TRANS ATHLETES FROM GIRLS SPORTS AT CONTENTIOUS MEETING

The California Interscholastic Federation governs public and private high school sports in the state and has a bylaw that requires its members to recognize gender identity in sports.

All students should be able to participate in school sports "in a manner that is consistent with their gender identity, irrespective of the gender listed on a student’s records," the bylaw states.

Dhillon, a former California-based conservative attorney, said the certifications she is seeking from the public school districts will "ensure compliance" with Title IX and help them to "avoid legal liability."

Her demand pits public school districts against the California Interscholastic Federation, the entity that schools are required to comply with to participate in state sports competitions.

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Fox News Digital reached out to the California Interscholastic Federation’s executive director for comment.

Dhillon's move comes after she and the U.S. attorney for the Central District of California announced last week that they were investigating the California Interscholastic Federation and other public entities over whether the state's laws conflicted with Trump's interpretation of Title IX.

When Trump took office, he ordered federal agencies to enforce Title IX in a manner that excluded gender identity after the Biden administration attempted to reinterpret the statute.

Title IX, passed in 1972, is a landmark civil rights law designed to prevent sex discrimination in schools. Former President Barack Obama made the first, albeit unenforceable, attempt to reinterpret Title IX at the end of his term by directing schools that received federal funds to allow transgender students to use bathrooms and participate in sports that corresponded to their gender identities.

Trump quashed those efforts in his first term and, in coordination with former Education Secretary Betsy DeVos, underwent a lengthy process of creating new rules within the Education Department to require schools to adhere to the long-held meaning of Title IX.

Former President Joe Biden made embracing gender identity and re-imagining Title IX a pillar of his presidency by moving to unravel the Trump administration's new rules. Biden was, however, met with numerous injunctions and never able to get his version of Title IX off the ground.

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Now, Trump has aggressively sought to enforce his first term's rules. He signed a string of executive orders focused on, as one order described it, the "biological reality of sex," and his agencies have sent demand letters and opened federal inquiries into states that are resistant to the administration's efforts.

In addition to targeting California, the DOJ sued Maine over Title IX, arguing its state Education Department was out of compliance with federal law, citing a transgender athlete who won a girls' pole-vaulting competition in February.

Maine Gov. Janet Mills (D) has downplayed the matter, telling local news at one point that there were "like two" transgender athletes in her state.

California Gov. Gavin Newsom (D), meanwhile, has shown an openness to Trump's position that transgender athletes competing in girls' sports is unfair, to the chagrin of some of Newsom's liberal base.

Newsom also recently said he supported a new pilot initiative by the California Interscholastic Federation to allow any female track and field athlete who would have qualified for an upcoming state championship to compete if they had been displaced by a transgender athlete.

A federal judge on Monday blocked the Trump administration from deporting a Venezuelan migrant under the Alien Enemies Act, saying it hasn't provided adequate notice or due process for it to be challenged. 

U.S. District Court Judge John Holcomb, a Trump appointee, ruled that those subject to deportation under the Alien Enemies Act have to be given a chance to challenge the move. 

"The Government is hereby preliminarily ENJOINED and RESTRAINED from removing or transferring out of this district any member of the putative class pursuant to the Proclamation pending further Order of this Court regarding the amount of notice and process that is due prior to removal," Holcomb wrote. 

In a win for Trump, Holcomb also said the president has "unlimited" authority to invoke the AEA, which is being challenged separately. 

Monday's ruling came amid a complaint by Darwin Antonio Arevalo Millan, a Venezuelan citizen being held at the U.S. Immigration and Customs Enforcement (ICE) facility in Adelanto, California.

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In his lawsuit, Arevalo said he is a "vocal dissident" of the Venezuelan government who was granted a permit authorizing him to work and reside in the U.S. pending the review of his asylum application.

He was arrested after he reported for a scheduled ICE check-in, his lawsuit states. The arrest was premised upon his status as a Venezuelan with allegedly basketball-related tattoos, which could indicate that Arevalo is affiliated with the notorious Venezuelan Tren de Aragua (TdA) gang, it said. 

Arevalo's complaint was filed on behalf of himself and other Venezuelan citizens subjected to Trump's AEA executive order proclamation. He is asking a judge to require the government to provide at least 30 days' notice before any removal or transfer. 

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Monday's ruling came days after the Supreme Court handed Trump a win by staying a lower court order that blocked the administration from deporting roughly 500,000 migrants from Cuba, Nicaragua and Venezuela.

The order stays the lower court ruling that halted Trump's plans to terminate Temporary Protected Status (TPS) protections for some migrants living in the U.S. TPS allow certain individuals to live and work in the U.S. legally if they cannot work safely in their home country due to a disaster, armed conflict or other "extraordinary and temporary conditions."

The TPS program is typically extended to migrants in 18-month increments, most recently under the Biden administration toward the end of his presidency. 

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However, Homeland Security Secretary Kristi Noem in February attempted to end protections for a specific group of Venezuelan citizens, saying they were not in the national interest. 

Fox News Digital's Breanne Deppisch contributed to this report.