The two automakers face a Tuesday deadline to submit completed restructuring plans, but neither company is expected to finish their work.

Moreover, GM is seeking US$16.6 billion more, while Chrysler wants US$5 billion more.

"What we are asking is difficult," Obama said on Monday. "It will require hard choices by companies. It will require unions and workers who have already made painful concessions to make even more. It will require creditors to recognize that they cannot holdout for the prospect of endless government bailouts."

"Only then can we ask American taxpayers who have already put up so much of their hard-earned money to once more invest in a revitalized auto industry," he said.

The Obama administration also replaced GM's CEO Rick Wagoner with the company's chief operating officer, Fritz Henderson.

If the automakers fall short, Obama raised the specter of using bankruptcy laws to force their restructuring.

The other one of the Big Three automakers, Ford, has said that it has enough cash to survive the downturn without government aid.

(Xinhua News Agency March 31, 2009)