Ford and General Motors are still pushing ahead with plans to sell their Swedish car brands while the Swedish government has ruled out more state aid or taking stakes.

Ford CEO Alan Mulally said in Detroit that he had talked with several potential bidders for Volvo while GM chief Rick Wagoner said his firm was still seeking a buyer for Saab.

GM Europe head Carl-Peter Forster said there had been an approach for Saab from "an investor" two or three months ago although this was currently on hold.

He dismissed speculation that a sale could be made before the end of March when GM has to present the US government a restructuring plan that shows the company is viable.

He added that it would not be possible to sell a business like Saab within two months.

GM product development chief Bob Lutz said the company had hoped for an improvement in Saab's finances for the nearly two decades it has owned the brand.

He said it had been on GM "life support" with an unending string of losses.

Mulally said there had been interest in Volvo but did not say from whom. Volvo chief Stephen Odell, who took over the job last autumn, did not comment on whether the company would be sold, only that he plans to make it profitable.

A senior official said in Detroit the Swedish government would not take stakes in either Saab or Volvo and does not plan to offer more aid to either.

"I made it clear to General Motors and Ford that under no circumstances will there be a way that the Swedish government, the Swedish state, will become an owner of either Volvo or Saab," Joran Hagglund, state secretary of the Swedish industry ministry, told Reuters at the show.

"They (GM and Ford) have to take the full responsibility for the actions that have to be taken to secure good futures for the brands of Saab and Volvo," Hagglund said.

Aid would be conditional on the money being spent in Sweden and would have to ensure the automakers' future viability and profitability.

Last month, the government said it would provide up to SKR25bn (US$3.1bn) in credit guarantees and emergency loans to its ailing auto industry.

Volvo is the last survivor of Ford's Premier Automotive Group which once included the British Aston Martin, Jaguar and Land Rover brands.

Aston was sold nearly two years ago to Middle East investors while Jaguar Land Rover was acquired by India's Tata Motors last year. Ford also sold about two-thirds of its stake in Mazda last November.