The federal government announced Wednesday, May 28, that it has launched an investigation into California school administrators, the California Interscholastic Federation and the Jurupa Unified School District for letting transgender athletes compete in girls’ sports.

Also, the U.S. Department of Justice sent a letter supporting a lawsuit filed by female Riverside Unified School District athletes that alleges the district violated their rights by ordering them to remove or conceal T-shirts opposing the practice of transgender athletes competing in girls’ sports and limiting their access to sports.

RELATED: Trump blasts Jurupa Valley transgender athlete set to compete in CIF State meet

The investigation will look into whether Title IX, a landmark federal civil rights law, is being violated by AB 1266, a 2013 state law permitting students to access bathrooms, sports teams and other facilities based on their gender identity.

Jurupa Unified School District spokesperson Jacqueline Paul said the district “has not received any letter of complaint from the DOJ, and their press release has been corrected to exclude our district in today’s announcement.”

The district declined to comment without further information, Paul said.

Ciaran McEvoy, a spokesperson for the U.S. Department of Justice, said the Jurupa district has been listed as a target of the investigation but is not part of the lawsuit, which involves the Riverside Unified School District.

The announcement comes a day after President Donald Trump, posted on social media that he will withhold federal funding from California if transgender athletes are allowed to compete in girls’ sports. His post is in response to AB Hernandez, an openly transgender athlete expected to compete at the CIF State Track and Field meet in the long jump later this week.

“THIS IS NOT FAIR, AND TOTALLY DEMEANING TO WOMEN AND GIRLS,” Trump wrote on his Truth social. “Please be hereby advised that large scale Federal Funding will be held back, maybe permanently, if the Executive Order on this subject matter is not adhered to.”

The probe was announced by the office of Bill Essayli, a former Corona Republican Assemblyman appointed in April to be U.S. attorney for the justice department’s Central District of California.

Hernandez, a junior from the Jurupa Unified School District in Riverside County has faced criticism online not only from Trump but from others, including Sonja Shaw, president of the Chino Valley Unified School District board. Shaw, who announced in March her run for state superintendent of schools, told City News Service that she’s been attending high school track and field meets to draw attention to Hernandez competing in girls’ events.

Shaw received a cease-and-desist letter from Nereyda Hernandez, Hernandez’s mother, over comments Shaw posted on her Instagram account. The comments were directed at AB Hernandez about what Shaw called biological males competing in high school girls’ sports.

A news release from the federal justice department said the investigation will look at whether California’s organizations and school districts are discriminating against female students on the basis of sex.

At the same time, the department is supporting a November lawsuit alleging that the Riverside school district violated students’ First Amendment rights and denied students fair and equal access to athletics. In the federal lawsuit, two students at Riverside’s King High School alleged that they were replaced on their cross country team in favor of a transgender athlete.

“Title IX exists to protect women and girls in education,” Harmeet K. Dhillon, assistant attorney general for civil rights, said in the release. “It is perverse to allow males to compete against girls, invade their private spaces, and take their trophies. This Division will aggressively defend women’s hard-fought rights to equal educational opportunities.”

The lawsuit against Riverside schools alleges that AB 1266 conflicts with Title IX and unlawfully “permits males to participate on female sports teams and to use female spaces, resulting in unfair and unsafe environments for women and girls.”

The lawsuit alleges a female student, referred to as T.S., was “ousted” from a spot competing at the October Mt. SAC Cross Country Invitational “to make room for a biological male transgender athlete who did not consistently attend practices and failed to satisfy many of the team’s varsity eligibility qualifications.”

“As a result, T.S. missed opportunities to compete at a high-profile meet, losing valuable chances for college recruitment and recognition,” the lawsuit alleges.

The transgender athlete received more favorable treatment than two female students “and other female athletes who have consistently satisfied many of the varsity eligibility qualifications,” the lawsuit alleges.

The suit also alleges that King High students opposed to the district’s actions wore T-shirts with the slogans “Save Girls’ Sports” and “It’s Common Sense. XX ≠ XY,” and were told by a school administrator that this was akin to wearing Nazi swastikas in front of Jewish students.

This is a developing story. Check back for updates.