Prosecutors on Thursday sought to use Bill Cosby's words against him at his sexual assault trial, showing interviews to jurors in which the comedian acknowledged giving his accuser pills before engaging in what he described as consensual "petting."

The introduction of Cosby's own statements on the trial's fourth day marked a new phase of the case after days of testimony from two of his accusers.

Cosby, 79, faces charges that he drugged and sexually assaulted Andrea Constand, a former employee of his alma mater Temple University, at his Philadelphia-area home in 2004.

The married star of the 1980's hit television family comedy "The Cosby Show" has faced similar allegations from dozens of women. He has denied all of the claims.

Only Constand's accusation has resulted in criminal charges because the other alleged incidents are too old to prosecute.

In a sworn deposition taken during Constand's 2005 civil lawsuit, which was later settled for an undisclosed sum, Cosby described an earlier encounter with Constand, when he began touching her midriff.

"Without talking, I'm asking if I can go farther," he said. "I don't hear her say anything, and I don't feel her say anything, and so I continue and I go into the area that is somewhere between permission and rejection. I am not stopped."

The deposition's unsealing in 2015 by a federal judge prompted prosecutors to reopen the case and bring charges later that year. Cosby also said he gave Constand 1-1/2 Benadryl pills on the night of the alleged assault after she said she was tense and sleep-deprived.

"I have three friends for you to make you relax," he said he told her.

Constand told jurors that she became barely conscious and unable to resist. In a police interview in 2005 that was also shown to jurors, Cosby said what followed was consensual "petting."

Cosby lawyer Brian McMonagle focused on discrepancies in Constand's 2005 statements to police, including her initial failure to mention the earlier encounter, when she said she rebuffed his advances.

Prosecutors on Friday are expected to continue presenting jurors with portions of Cosby's deposition, including his admission that he gave the sedative Quaalude to young women.