Bryant is one of the top-earning sportsmen in the US

The surprise move comes less than a week after the start of jury selection in Mr Bryant's trial in Colorado.

Prosecutors asked the judge to dismiss the case because the alleged victim refused to testify, US TV reports say.

The 26-year-old Los Angeles Laker star denies assaulting a teenager at a ski resort last year, saying sex between them was consensual.

The US network ABC said the alleged victim - who is now 20 - would not appear in court.

"The prosecution could not have proceeded without the alleged victim in this case," ABC said.

However AFP news agency reports that under a deal negotiated by the prosecution and Mr Bryant's lawyers, a civil lawsuit filed against the star by the woman will proceed.