Andrew Tate choked his girlfriend Bri Stern with one hand and used his other mitt to beat the crap out of her face ... according to a new lawsuit.

Bri is suing Andrew for sexual assault and battery and gender violence ... and in her lawsuit, she goes into more detail on the alleged choking incident she filed a police report over.

In the docs, obtained by TMZ, Bri says they were having consensual sex in his room at The Beverly Hills Hotel when things suddenly changed and he started being verbally degrading and violent.

Bri claims Andrew routinely degraded her during sex -- but on this night things were "much worse, more aggressive and more violent." She claims he started choking her and would not stop despite her crying and begging for him to stop, with her cries and screams only causing Tate to hurt her more.

Andrew's ex says he continued choking her harder and harder, making her nearly lose consciousness ... claiming he used one hand to choke her and used the other to beat her repeatedly on the side of her face and the top of her head.

She also claims Andrew threatened her during the alleged assault, telling her if she ever crossed him he was going to kill her. She says she sobbed and pleaded and protected herself as best she could until Andrew climaxed and the attack subsided.

Bri says she wanted to leave after the attack but was too scared ... and the following morning she pretended like nothing happened so she could finally escape Andrew's hotel room, ultimately seeing a physician before reporting the attack to police.

She says Andrew manipulated and groomed her from the moment they met in Romania last summer, when he booked her for a modeling gig ... filling her head with lies and love-bombing her.

Bri says Tate first came off as charming but then showed his true colors when he started degrading and threatening her ... she says he would call her his "property," an "idiot," a "w****" and "just a hole."

She also claims he would threaten her while assaulting her, telling her ... "If you ever f*** with me, I will f****** kill you. I mean it. I will kill you."

Bri even says Andrew threatened to sex traffic her, keep her in Romania and rape her.

As you know ... Andrew and his brother Tristan were arrested back in 2022 for allegedly creating a criminal organization in Romania, and Andrew's been charged with rape in that country. They're also both facing sexual assault lawsuits in the U.S. and the UK. They have not been convicted of any crimes.

Bri hired Texas attorney Tony Buzbee, who is representing over 100 alleged Diddy sexual assault victims, to represent her in this lawsuit, filed in California.