A US appeals court has unanimously rejected a petition filed by Napster in which the company sought a re-examination of the injunction handed down against it earlier this year.

A three-judge panel of the Ninth Circuit of the Court of Appeals found that Napster infringed on record-company copyrights through the operation of its music file-trading service. Napster then asked that the entire court look at the case, instead of only the three-judge panel.

Court documents filed last week show that all the judges in the Ninth Circuit denied Napster's request. The court's ruling marks just one part of a lengthy battle between Napster and music labels represented by the Recording Industry Association of America (RIAA).

The injunction against Napster sets restrictions on the company's service, while both sides await the beginning of the trial, whose date hasn't been set yet.

Napster has said it will move to what will effectively be a two-tiered subscription service by the third quarter. A basic service will include songs from small artists and independent record labels, while a premium service allow users to trade songs from the major labels.