CHICAGO (AP) - Prosecutors charged R&B singer R. Kelly on Thursday with 11 new sex-related counts, including some that carry a maximum sentence of 30 years in prison, making them the most serious against him.

Cook County prosecutors charged the Grammy award-winning singer with four counts of aggravated criminal sexual assault, two counts of criminal sexual assault by force, two counts of aggravated criminal sexual abuse and three counts of aggravated criminal sexual abuse against a victim who was at least age 13 and under 17 at the time, The Chicago Sun-Times reported, citing court documents it posted on its website.

The four aggravated criminal sexual assault counts carry maximum terms of 30 years in prison.

Kelly was already facing 10 counts of aggravated sexual abuse involving four women years ago, three of whom were minors when the alleged abuse occurred.

The new charges apparently pertain to a single victim, identified in the court filing by the initials "J.P." It isn't clear if she is the same person as one of the initial four accusers who also was identified by the same initials in court documents.

According to the filing, the first eight counts are from encounters that allegedly occurred between Jan. 1 and Jan. 31, 2010. Three others pertain to alleged encounters between May 1, 2009, and Jan. 31, 2010.

Among other things, prosecutors allege that Kelly used force or threatened to do so to pressure the accuser into sex or to perform oral sex on him. She was underage at the time, extending the statute of limitations for bringing charges to 20 years from her 18th birthday, they wrote.

Kelly pleaded not guilty to the original charges and denied any wrongdoing after his February arrest. The AP couldn't immediately reach him for comment about the new charges.

Kelly's defense attorney, Steve Greenberg, didn't immediately respond to an email from the AP seeking comment. He told the Sun-Times that he had received word of new charges from prosecutors but hadn't seen any filings in the case. He did say he understood that the allegations are "from years ago."

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