Federal prosecutors in a Monday letter said they “strenuously oppose” R. Kelly’s bid to postpone the sentencing date for his sex trafficking convictions in New York.

In their letter to Brooklyn federal court Judge Ann Donnelly, prosecutors argued that Kelly’s victims “have waited years” to see the disgraced R&B singer “held to account” and sentenced.

The pointed remarks came in response to a motion filed last Tuesday by Kelly’s new attorney, Jennifer Ann Bonjean — asking Donnelly to delay the 54-year-old singer’s scheduled May 4 sentencing until after he is tried separately in Illinois in August on federal charges of child pornography and obstruction of justice.

Kelly was convicted in September on all nine counts against him — including racketeering and violations of the Mann Act, which prohibits the transport of “any woman or girl” across state lines for any “immoral purpose.” He faces 10 years to life in prison.

Bonjean, in her request, expressed concerns that any potential testimony made by Kelly to a mitigation expert for his sentencing hearing could be used against him in his Illinois case, according to the letter.

The lawyer wrote that she “cannot advise Mr. Kelly to be examined or interviewed by a mitigation expert for sentencing in this case if his words might be used against him in some manner in his pending NDIL trial,” the letter said.

But prosecutors dismissed her argument as “speculative concern.” They argued it “strains credibility that [Kelly] would say anything to a potential mitigation expert that would incriminate him” in his other case.

Prosecutors added that they would not share any such mitigation report with the prosecutors from the Northern District of Illinois, and would “would welcome a court order further prohibiting any such disclosure.”

“As proven at trial, the defendant engaged in wide-ranging and extensive criminal conduct, involving multiple victims, with impunity for decades,” prosecutors wrote in the letter. “His victims have waited years to see the defendant held to account and sentenced for his crimes.”

They said many victims have already scheduled to travel to New York for the May 4 sentencing.