Brittney Griner's Detention In Russia Extended, Request For House Arrest Denied

Brittney Griner will remain in custody in Russia for at least another month ... a judge just denied her request for house arrest, forcing her to stay in jail for another 30 days.

The 31-year-old WNBA superstar appeared in a Russian courtroom on Friday morning with the hopes of getting out of jail ... but her attorney told the Associated Press that did not happen.

The attorney, Alexander Boikov, did say, though, that because of the short nature of the custody extension ... he did believe a trial in Griner's case might be coming soon.

Griner wore an orange sweatshirt to Friday's hearing, and left the courtroom with a hood up over her head. In photos of her leaving her appearance, you can see she was wearing cuffs on her wrists.

As we reported, Griner has been in custody in Russia since February -- after she allegedly had hash oil in her luggage at an airport.

She's now had her requests for house arrest denied at least two times by judges as her pre-trial detention has dragged on.

United States officials, meanwhile, have classified her as "wrongfully detained" ... and are attempting to negotiate her release.