General Motors will stop supplying technology to Saab if it is is bought by Chinese investors, according to a report by the BBC.
The news could scupper Saab's sale to Chinese firms Pang Da Automobile Trade and Zhejiang Youngman, which last month agreed to buy the ailing company for £86m.
"Although General Motors is open to the continued supply of powertrains and other components to Saab under appropriate terms and conditions, GM will not agree to the continuation of the existing technology licenses or the continued supply of 9-4X vehicles to Saab following the proposed change in ownership as it would not be in the best interests of GM shareholders," GM spokesman Jim Cain said.
Victor Muller, chief executive of Saab's current owner Swedish Automobile, said that negotiations would now have to go "back to the drawing board".
GM, which sold Saab to Muller in 2010, said it would block existing technology licences and stop supplying the Saab 9-4X.