Washington, United States + US President Joe Biden called for an end to discrimination Thursday after an autopsy found a nonbinary teenager died by suicide a day after clashing with three other students.

The case of Nex Benedict, 16, from Oklahoma, had drawn widespread outrage and calls for change in the way trans and nonbinary people are treated.

"Nex Benedict, a kid who just wanted to be accepted, should still be here with us today," Biden said in a statement, adding that he and First Lady Jill Biden were "heartbroken" by the teen's death on February 8.

"Nonbinary and transgender people are some of the bravest Americans I know. But nobody should have to be brave just to be themselves."

Democrat Biden called for work to end discrimination and to address the "suicide crisis impacting too many nonbinary and transgender children."

"Bullying is hurtful and cruel, and no one should face the bullying that Nex did," he said.

Benedict identified as nonbinary, a term used by people who see their gender identity as falling outside the categories of "man" and woman," according to the GLADD advocacy group. Many nonbinary people also consider themselves transgender.

Benedict reported being in an altercation with three girls in a restroom in their high school in the city of Owasso.

Benedict was seen by a school nurse but was sent home and police were not contacted until Sue Benedict, the student's grandmother and legal guardian, phoned later in the day from a hospital emergency room.

In a video released by police, Nex Benedict told police from a hospital bed that Nex had poured water on three girls after being mocked over "the way that we dress... All three of them came at me."

The following day Nex Benedict fell ill at home, was rushed back to the hospital, and died.

Sue Benedict and others told local media the teen had been bullied by fellow students for more than a year, including over the way that they dressed.

An autopsy report released Wednesday said found a toxic mix of pharmaceutical drugs, US media reported.

The US Education Department said on March 1 it was opening an investigation into whether the school district had failed to respond appropriately to "sex-based harassment."

The case tapped into a growing culture war over gender issues in an increasingly polarized United States.

Oklahoma is one of a number of Republican-controlled states that have passed laws prohibiting students from using bathrooms not in alignment with their sex at birth.

It also bans gender-affirming care for minors.