R Kelly sexually assaulted a woman at his Chicago studio nearly two decades ago, where he locked her up without food and water, the woman testified at the R&B singer's trial today.

The woman, who identified herself as Sonia, told jurors in Brooklyn federal court she was kept at least two days in a locked room at Mr Kelly's Chocolate Factory studio in 2003.

Sonia said that after finally being allowed to eat she became "extremely full" after a few bites and "felt something coming over" before falling asleep.

She said Mr Kelly was adjusting his pants when she woke up. Under questioning by Assistant US Attorney Maria Cruz Melendez, she said she recalled feeling that something had happened to her and believed she had been sexually assaulted.

On cross-examination, Mr Kelly's lawyer Deveraux Cannick questioned why Sonia did not immediately call police or see a doctor, waiting instead until the 2019 Lifetime documentary Surviving R. Kelly described Mr Kelly's other alleged abuses.

Sonia later told Ms Melendez she did not think anyone would believe her, and that she had been scared of Mr Kelly.

Mr Kelly, 54, whose full name is Robert Sylvester Kelly, has pleaded not guilty to nine criminal counts for running an alleged decades-long racketeering scheme targeting women and girls, with help from people he employed.

The indictment describes Mr Kelly's alleged treatment of six women and girls, including the late singer Aaliyah.

Several women, including some not identified in the indictment, have testified about Mr Kelly's alleged abuses.

The trial before a seven-man, five-woman jury began on 18 August. Today's session was the first since 3 September.

Sonia said she had travelled to Chicago to interview Mr Kelly for a Utah radio station, where she had been a 21-year-old intern.

She testified that she signed two nondisclosure agreements, neither of which she read, upon arriving at and before leaving the Chocolate Factory.

Sonia also said she was admonished before leaving not to cross Mr Kelly, with an obscenity added for emphasis, which she took as a threat. The interview never occurred, she said.

Mr Kelly's lawyers have been trying to show that the singer's accusers wanted to be with him.

Sonia told Mr Cannick the Utah radio station would not arrange her travel to Chicago, so she went on her own, with Mr Kelly's team handling the logistics.

But when asked why she did not read the second non-disclosure agreement, after the alleged assault occurred, Sonia told Mr Cannick: "I just wanted to go home."

Known for songs such as the Grammy-winning I Believe I Can Fly and Bump N' Grind, Mr Kelly has faced sexual abuse accusations for nearly two decades.

Scrutiny increased after the #MeToo movement began and Lifetime documentary aired. Mr Kelly has been jailed for more than two years, and also faces sex-related charges in Illinois and Minnesota.