Swedish luxury carmaker Koenigsegg and Norwegian investors have signed a preliminary deal to buy General Motors' unit Saab, a source familiar with the matter said on Thursday.

The source confirmed an earlier report by Swedish television that a letter of intent had been signed between the parties.

The deal is there now and a few minor details remain, said the source who declined to be identified.

Saab was not immediately available for comment.

Saab Automobile, which was put up for sale by its now bankrupt U.S. parent earlier this year, had been in talks with two or three bidders in the past weeks.