R Kelly has sued the Brooklyn jail that has housed him since his racketeering and sex crimes conviction, saying it wrongly put him on suicide watch.

In a complaint filed in Brooklyn federal court, the 55-year-old multi-platinum R&B singer said officials at the Metropolitan Detention Center ordered the watch after his June 29 sentencing “solely for punitive purposes” and because he was a “high-profile” inmate.

Kelly received a 30-year prison sentence.

His lawyer Jennifer Bonjean quoted a prosecutor as saying the jail’s legal counsel told her that “per the psychology department, (Kelly) is on a psych alert for various reasons, such as age, crime, publicity and sentencing”. No timetable was provided.

Bonjean wasn’t satisfied with the explanation.

“Simply put, MDC Brooklyn is run like a gulag,” she wrote.

Kelly said the “harsh conditions” he faced led to “severe mental distress”, and amounted to cruel and unusual punishment that violated the US Constitution’s Eighth Amendment.

He is seeking unspecified compensatory and punitive damages, though the docket suggests Kelly is seeking $US100 million ($A148 million).

The jail did not immediately respond to requests for comment.

Known for the 1996 Grammy-winning hit ‘I Believe I Can Fly’, Kelly was convicted last September on one count of racketeering and eight counts of violating the Mann Act, which bars transporting people across state lines for prostitution.

Prosecutors said Kelly exploited his stardom and wealth over two decades to lure women and underage girls into his orbit for sex, with the help of his entourage.

Kelly still faces an August trial in Chicago federal court on child pornography and obstruction charges, and various state charges in Illinois and Minnesota.

-AAP