UPDATE VIA TMZ:

9:10 AM PT — Federal prosecutors in Brooklyn want to make sure Kelly remains behind bars until trial. In a letter to a federal judge, they say Kelly is a significant flight risk … and his decades-long criminal history make it clear he’s a danger to the community. They also fear he will obstruct justice and “threaten and intimidate potential witnesses.”
Kelly’s scheduled to have a bail hearing next week.

R. Kelly was arrested Thursday night in Chicago on federal child pornography and obstruction of justice charges, the U.S. attorney’s office in Chicago said.

He was arrested by NYPD detectives and Department of Homeland Security investigators. The rapper is expected to be brought to New York City.

“R Kelly was arrested in Chicago tonight on charges contained in a 13-count indictment returned today in the Northern District of Illinois,” the attorney’s office said in a statement late Thursday. “The indictment includes charges of child pornography and obstruction of justice.”

Kelly’s publicist confirmed the rapper was arrested on federal sex crime charges and is in police custody. He said a news conference is planned for Friday morning. Kelly’s attorneys have not commented on the latest round of charges.

R. Kelly in February was charged with aggravated sexual abuse involving four women, three of whom were minors. He pleaded not guilty and was released from jail after posting bail. [Radio]