US President Donald Trump had a heated exchange with a Democratic governor Friday over his order barring transgender athletes from women's sports, with the state leader telling him: "See you in court."

The Republican president was making televised remarks to a gathering of the country's governors at the White House when he raised the executive order he signed earlier this month.

"Two weeks ago I signed an executive order banning men from playing in women's sports. Many Democrats are fighting me on that, I hope you continue because you'll never win another race," he said.

The ban is "to protect women," he claimed.

"Are you not going to comply with it?" he asked Janet Mills, governor of the northeastern state of Maine.

"I'm complying with state and federal laws," Mills responded.

"Well, we are the federal law... You better do it, because you're not going to get any federal funding at all if you don't," the president said.

"See you in court," she responded.

"Good, I'll see you in court. I look forward to that. That should be a real easy one. And enjoy your life after governor, because I don't think you'll be in elected politics," a visibly angry Trump replied.

Trump's order allows US government agencies to deny funds to schools that allow transgender athletes to compete on women's teams.

Some Maine officials have said they will continue a policy of allowing transgender students to choose which team they play on, citing state law under the Maine Human Rights Act, according to the Portland Press Herald.

Mills and the state's attorney general have vowed to fight any move to deny the state federal funds, the newspaper reported.

'Violation'

Later Friday, the Department of Education's Office for Civil Rights announced an investigation into Maine's education department for alleged violations of Title IX, the landmark civil rights law that forbids discrimination on the basis of gender in educational facilities that receive federal support.

A statement cited allegations that Maine's education department "continues to allow male athletes to compete in girls' interscholastic athletics and that it has denied female athletes female-only intimate facilities, thereby violating federal antidiscrimination law."

Craig Trainor, DoE acting Assistant Secretary for Civil Rights, said Maine must comply with Title IX to continue receiving federal funds.

"If it wants to forgo federal funds and continue to trample the rights of its young female athletes, that, too, is its choice," he said in the statement.

Mills called it a "politically directed move" to strip funding "paid for by Maine taxpayers."

"This is not just about who can compete on the athletic field, this is about whether a President can force compliance with his will, without regard for the rule of law that governs our nation," she added.

Republicans hammered Democrats on transgender issues — especially when it came to youth and sports — ahead of the 2024 election, capitalizing on a broader culture war over LGBTQ rights.

Since his return to power, Trump has demonized any recognition of gender diversity, attacking transgender people — a small minority of the population — and gender-affirming care for minors in both his rhetoric and in executive orders.

Trump has said he will also push the International Olympic Committee to change its rules on transgender athletes before the 2028 Los Angeles Games.