Donald Trump has signed an executive order banning trans women athletes from competing in female sports.
The move is designed to prevent people who were biologically assigned male at birth from participating in certain sporting events, including those at school.
The order, titled "Keeping Men Out of Women's Sports", will call for "immediate enforcement" against schools and athletic associations that deny women single-sex sports and single-sex changing rooms.
It also coincides with National Girls and Women in Sports Day and it marks another notable shift in the way the federal government treats transgender people under Mr Trump.
Follow live: Donald Trump latest
Ahead of signing the order, Mr Trump said: "From now on women's sports will be only for women.
"We've gotten the woke lunacy out of our military and now we're getting it out of women's sports."
He also spoke about the coming Olympics and World Cup which the US is hosting, and said he wouldn't allow any transgender athletes to compete.
He went on: "In Los Angeles in 2028, my administration will not stand by and watch men beat and batter female athletes.
"We're not going to let it happen.
"Just to make sure, I'm also directing our secretary of homeland security to deny any and all visa applications made by men attempting to fraudulently enter the US while identifying as women athletes to try and get into the games."
In signing the order, surrounded by a number of women and girls, Mr Trump claimed "the war on women's sports is over".
The order authorises the education department to penalise schools that allow transgender athletes to compete and any school found in violation could lose its federal funding.
Despite their small numbers within America, transgender people have been the target of three orders signed by Mr Trump since coming into office, Sky News' US partner NBC News reported.
These targeted participation in the military and access to gender-affirming care.
On his very first day in office last month, Mr Trump passed one order that called on the federal government to only recognise two genders - male and female.
During his campaign, he pledged to "keep men out of women's sports" and get rid of the "transgender insanity" but his office offered little in the way of details.
Olivia Hunt, director of federal policy at Advocates for Trans Equality, told Sky News' Yalda Hakim that the order wasn't just about elite athletes but would impact young children and their development too.
She said: "We're basically taking those children and saying to them we don't think it's vital that you learn the same sets of skills that your peers develop [playing sports].
"We are setting you aside, putting you apart, and saying you're different and it's okay for you to be set aside, treated differently, and bullied by your peers.
"Children should be protected. Children should be allowed to follow their interests, follow the sports they want to participate in and not have to worry that public officials will treat their existence as a cheap round of applause."
This is the latest in a flurry of executive orders the Republican president has enacted in his first days and weeks in office.
Some of these have been blocked by judges, and it is not yet clear if this order will avoid such a fate.
It will likely involve how the Trump administration interprets Title IX - a civil rights law that prevents sex-based discrimination in education programmes or activities that receive federal funding.
Ahead of the signing, White House press secretary Karoline Leavitt said the order "upholds the promise of Title IX".
Read more:
Trump says Iran would be 'obliterated' if it assassinates him
Why China has not retaliated more in trade spat
What you need to know about Trump's Gaza plan
'A solution looking for a problem'
It is not clear how many trans athletes are competing in the US, but cases like Lia Thomas swimming for the University of Pennsylvania have drawn attention in the past.
Cheryl Cooky, a professor at Purdue University who studies the intersection of gender, sports, media and culture, described the order as a "solution looking for a problem".
? Listen to Sky News Daily on your podcast app ?
Doriane Lambelet Coleman, a professor at Duke Law School, pointed out that Mr Trump could have just "read the [existing] regulation traditionally" to achieve the same goals, instead of introducing the new executive orders.
(c) Sky News 2025: Donald Trump signs executive order banning trans women athletes from competing in female sport