Some of R&B superstar R. Kelly’s peers in the music world are denouncing him as a “child molester” while Chicago ministers step up their boycott against stations that play his music.

Police and prosecutors are investigating a video that appears to show Kelly having sex with a 14-year-old girl, violating statutory rape and child pornography laws.

“Thong Song” rapper Sisqo’s new track, “This Is the Heart,” offers the lyric “Let me remind you of that ish you did. ‘The World’s Greatest?’ Whatever! Ain’t nothing but a child molester.”

Kelly insulted Sisqo on “The Best of Both Worlds,” the album he released with rapper Jay-Z last month. The album sold far less than expected. Industry executives blame the scandal. Jay-Z refused to tour, make videos, or even be photographed with Kelly after the police probe was disclosed.

Rapper Nas recently told an L.A. audience, “We’re not up here molesting children. We’re not ‘The Best of Both Worlds.’ ”

Multiplatinum producer Dr. Dre has decided not to release a track with Kelly and the group Truth Hurts. Dr. Dre told the British newspaper New Nation last week, “I’ve been hearing a lot of talk on the radio from stations that are saying they are not going to play his records ever again because they saw the video, and he’s a sick bastard. But I don’t know if it’s true. I only know what I’ve heard. I haven’t seen the video, nor do I want to see it because there’s a kid involved. That’s where I draw the line. You can do almost anything except touch kids or something like that. That’s a no-no. You know what I’m saying? If he’s guilty, he’s over. I’m just waiting for the results.”

In Chicago on Thursday, the Rev. Bamani Obadele’s Operation Defense group launched a letter-writing and telephone campaign asking Burger King and Ameritech, two of WGCI radio’s biggest advertisers, to pull their ads until the station drops R. Kelly’s music.

“We’re demanding a meeting with R. Kelly because the ‘R’ in his name should be for Righteous Kelly, not Reckless Kelly,” said the Rev. Al Sampson, the group’s co-chairman. “At the bare minimum, he needs to have pastoral counseling because something is wrong, and we are prepared to listen to him.”

WGCI president and general manager Marv Dyson said Kelly’s “Get This Money” was the second-most requested song at the station.

“The man is innocent until proven guilty. Until he’s had his day in court, or at least based on the information I have today, I just don’t feel it’s fair to take his music off the radio,” Dyson said.

B-96 program director Todd Cavanah said Thursday that Kelly’s music was pulled off the air, but not because of the protests. Songs from Kelly’s CD with Jay-Z simply aren’t that great, Cavanah said.

Kelly has launched a public relations move that may divert attention from the scandal.

He has recorded a tribute to American soldiers fighting in Operation Enduring Freedom called “Soldier’s Heart.” It will hit radio stations Monday and will arrive in record stores April 23. Proceeds will benefit charity.

“The timing is nothing more than mere coincidence,” said Kelly spokesman Bernie Roswig. “With all the things happening in Afghanistan and the Middle East, he just thought it would make sense to put the song to good use.”

A supervisor of the Chicago police sex crimes unit said they are well aware that the R. Kelly video is being sold on the streets in Chicago and other major cities, including New York, Los Angeles, Atlanta and Philadelphia. “I do not have an answer for every jurisdiction in every state,” the supervisor said. “My entire thing here is to focus on our investigation here in the state of Illinois.”

Added the police official: “I’m concerned with the victim; that’s my focus right now. The only thing I can say is the investigation is progressing, and we’re working in conjunction with the state’s attorney’s office. This will finish at some point.”