American singer R. Kelly has been convicted of exploiting his superstar status to run a scheme to sexually abuse women and children over two decades.

Eleven victims, including nine women and two men, appeared in court over the six-week trial to testify about the abuse and violence.

After two days of deliberation, the jury found Kelly guilty on all nine charges he was facing, according to a BBC report.

Sentencing is due on 4 May and he could spend the rest of his life behind bars.

The jury found Kelly, whose full name is Robert Sylvester Kelly, was the ringleader of a violent and coercive scheme that lured women and children so that he could sexually abuse them.

The singer – most famous for the hit songs I Believe I Can Fly and Ignition (Remix) – was also found to have trafficked women between different US states.

Along with eight counts of sex trafficking, Kelly was found guilty of racketeering, a charge normally used against organised crime associations.

"Today's guilty verdict forever brands R. Kelly as a predator, who used his fame and fortune to prey on the young, the vulnerable and the voiceless for his own sexual gratification," CNN cited Jacquelyn Kasulis, acting US attorney from the Eastern District of New York, as saying.

R. Kelly is "a predator who used his inner circle to ensnare underage girls and young men and women for decades, in a sordid web of sex abuse, exploitation and humiliation," Kasulis added.

Attorney Gloria Allred, who represented three of the six victims who testified at trial, said Kelly is the worst predator she has ever pursued.

"First, he used the power of his celebrity to recruit vulnerable underage girls for the purpose of sexually abusing them. These were not May-October relationships, which is what his defence attorney wanted the jury to believe — these were crimes against children and some adults," Allred said, according to CNN.

She said the verdict was also a message to other celebrities who indulged in such predatory  activities.