General Motors' (GM) auditors have revealed that there is "substantial doubt" about the company's future.
If a large restructuring plan cannot be implemented, GM said it could have to seek bankruptcy protection.
The company's worries were raised in an annual report filed with the Exchange Commission and US Securities.
Auditors for accounting firm Deloitte & Touche LLP said in the report: "The corporation's recurring losses from operations, stockholders' deficit, and inability to generate sufficient cash flow to meet its obligations and sustain its operations raise substantial doubt about its ability to continue as a going concern."
The motoring industry is facing the worst sales in years and to try to stay afloat GM received $13.4 billion (£9.5 billion) in government funding.
It is now hoping for a total of $30 billion (£21 billion) from the US Government, and over the past three years has made $82 billion (£58 billion) in losses.
GM has a March 31 deadline to sign agreements of concessions from creditors and the United Auto Workers union to show the Government it can become viable again.
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