A lawyer for R. Kelly says he is being kept in solitary confinement at an Illinois federal lockup and asked a judge Thursday to release him into the general inmate population, saying his Constitutional rights are being violated. The disgraced R&B singer is accused in several state and federal indictments of sex crimes involving women and girls that span decades.

The Federal Bureau of Prisons (BOP) would not comment on the conditions of Kelly's pre-trial confinement at Chicago's Metropolitan Correctional Center. But in an Illinois court filing, Kelly's lawyer, Steve Greenberg, pointed to a Monday e-mail from an unidentified BOP official indicating Kelly was being held in administrative detention — when an inmate is segregated from the general population for non-punitive reasons — for his own safety.

"The issue is that although he may be ready to go to general population, for safety and security reasons, he may not be appropriate for general population at this time because of his alleged offense and notoriety," the email said.

In the court filing, Greenberg said Kelly, 52, has been kept in solitary segregation since his July 11 arrest, though he hasn't violated any rules. Greenberg argued that Kelly is being "punished because of the crime of which he is charged and because of his celebrity status."

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The filing says Kelly has "no meaningful interactions with other humans," no time outside or recreation privileges, limited visitation, no television or e-mail and is only allowed to shower three times a week. It points to concerns about the use of solitary confinement, which experts say can trigger or exacerbate mental illness and says the segregation violates Kelly's Constitutional protection from cruel and unusual punishment.

Greenberg also argues that less restrictive housing options are available, but BOP has not utilized them.

In the email cited by Greenberg, the BOP official notes a federal prisons policy that allows an inmate's placement in administrative detention at the discretion of the warden "when their continued presence in the general inmate population poses a serious threat to themselves or others." It says Kelly's detention status would continue to be reviewed weekly and that he was being monitored daily by psychologists and medical staff.

R. Kelly seen in a mugshot March 6, 2019. Cook County, Illinois, Jail

U.S. District Judge Harry Leinenweber, who last month ordered Kelly held without bond, is scheduled to take up the motion on Wednesday, according to online court records.

Kelly faces federal sex crime charges in New York and Illinois, sex assault and sex abuse charges in Cook County, Illinois and solicitation charges in Hennepin County, Minnesota.

The New York indictment alleges Kelly for two decades ran a racketeering enterprise comprised of "managers, bodyguards, drivers, personal assistants and runners" who recruited women and girls for sex with Kelly and transported them around the country. It outlines allegations by five unnamed victims.

The federal indictment in the northern district of Illinois outlines allegations by five additional victims and accuses Kelly of having sex with five minors in the late 1990s and early 2000s, recording some of the alleged abuse on multiple videos.

Kelly has maintained his innocence, including in an explosive interview with CBS News' Gayle King.