A teenager who sang the US national anthem at President Donald Trump's inauguration in January has asked him to sit with her and her transgender sister to learn about the challenges facing students struggling with gender identity.

Jackie Evancho, 16, requested the meeting in a public Twitter message to the president late on Wednesday, minutes after his administration revoked landmark guidance to public schools to let transgender students use the bathrooms of their choice.

"I am obviously disappointed in the @POTUS decision to send the #transgender bathroom issue to the states to decide. #sisterlove," she wrote from her account, @jackieevancho.

Trump "gave me the honor" of singing at the inauguration, she added. "Pls give me & my sis the honor 2 meet with u 2 talk #transgender rghts."

White House spokesperson Sean Spicer, asked at a briefing if Trump would meet with Evancho, said the president would welcome a meeting with her.

As of yesterday morning, more than 6,300 Twitter users had liked the request by Evancho, a classical crossover singer who rose to fame on the TV show 'America's Got Talent'.

Evancho was the first performer announced for Trump's inauguration ceremony, an event that a number of other entertainers shunned because of the president's views.

Trump, a Twitter user, has not responded to the request, Evancho said yesterday during an appearance with her sister, Juliet, on ABC's 'Good Morning America'.

"I just want to enlighten him on what my sister - I've seen her go through every single day in school," she said.

Juliet Evancho, a high school senior, said the president needed to know about the threats facing students who identify as a gender other than the one with which they were born.

"I've had things thrown at me," she said. "I've had people say pretty horrible things, and the unsafe environment is just very unhealthy."

The Evancho family is suing Juliet's Pittsburgh-area school district over her right to use women's bathrooms.

The Trump administration's action on Wednesday reversed a signature initiative of former president Barack Obama, whose Justice and Education departments had threatened to withhold funding for schools that did not comply with its guidance.

- Reuters