The ex-Olympic athlete and reality TV star said she had "remained hopeful" that she could work with Mr Trump's administration.

But in a column for the Washington Post on Thursday, she admitted her position had been a "mistake".

"The reality is that the trans community is being relentlessly attacked by this president," she wrote.

The president has faced strong criticism in recent days after the New York Times reported the government was considering officially defining gender as biological and fixed.

• Outcry over 'proposed change' to US trans law

The change would rescind previous policy which eased trans recognition and would instead define gender solely by the genitalia people are born with.

In her column, Ms Jenner accused the president of using the trans community as "political pawns".

"The leader of our nation has shown no regard for an already marginalized and struggling community," she added. "He has ignored our humanity. He has insulted our dignity."

Last year, Ms Jenner told the BBC that she had been "really upset" by some of the president's policies, including his decision to revoke Obama-era guidance which allowed transgender students to use school toilets matching their gender identity.

"It doesn't make me regret my vote yet, but it is very disappointing and I have been very verbal about that," she said at the time.

The same year, Mr Trump also reinstated a ban on transgender people serving in the military which had been lifted by former President Barack Obama. He later signed a more limited directive after federal judges ruled the initial ban was probably unconstitutional.