Detroit ? Prosecutors made a “limited-time offer” Friday to Mayor Kwame Kilpatrick: Resign by Sept. 3 in exchange for the dismissal of one of two assault charges against him. Kilpatrick rejected the deal, which a mayoral spokesman dismissed as grandstanding.

Attorney General Mike Cox’s office offered the plea deal to the mayor, who also is charged with perjury and other counts in a separate case dealing with his sworn denials of an affair.

“It’s an offer we feel would satisfy the ends of justice,” special prosecutor Doug Baker told reporters outside the courtroom. “And if it can settle the case, then we would be happy with it. If not, then we go to trial.”

Kilpatrick, Detroit’s mayor since 2002, is accused of shoving a sheriff’s detective into another investigator while they tried to serve a subpoena on a Kilpatrick friend July 24. A not-guilty plea was entered at the 38-year-old Democrat’s arraignment Friday.