MINNEAPOLIS - A federal judge has blocked a sound engineer from releasing unpublished music by Prince after the late superstar's estate objected.

George Ian Boxill worked with Prince on five tracks in 2006, and made at least one recording -- called "Deliverance" -- available Wednesday for online sales. Prince's estate and Paisley Park Enterprises sued to block it.

U.S. District Judge Wilhelmina Wright late Wednesday granted a temporary restraining order to stop the songs' release, and ordered Boxill to deliver the recordings to the estate. Wright said she would schedule a hearing later on a preliminary injunction.

The estate's lawsuit said Boxill signed a 2004 confidentiality agreement that the recordings would remain Prince's sole property. Prince sings and plays guitar and keyboard on the tracks.