Washington - Some of the United States' largest banks will be forced to raise billions of dollars more in cash to survive the ongoing financial crisis, according to the findings of government regulators to be released Thursday.

The US Federal Reserve will issue the much-anticipated details of the so-called stress tests, which evaluated the country's 19 largest banks, after markets close Thursday afternoon.

At least seven banks will require capital infusions of 65 billion dollars, the Wall Street Journal reported, citing unnamed sources ahead of the announcement.

The stress tests lie at the centre of President Barack Obama's effort to nurse the US financial system back to health, which is considered the only means of pulling the United States out of a wider economic downturn considered one of the worst since the Great Depression.

But for many investors, the results of the months-long review - overseen by a number of government regulators - are demonstrating that most banks may not be quite as insolvent as expected. US markets jumped more than 1 per cent Wednesday as details began to emerge.

Treasury Secretary Timothy Geithner, in an opinion piece in The New York Times, said he expected the results would be "reassuring" to the markets and encourage private investors to jump back into the financial sector.

"The effect ... will be to help replace uncertainty with transparency," Geithner said.

The stress-test results could prompt the Obama administration to take a more hands-on approach to Wall Street, forcing some banks to give the government increasing shares and even make changes in top management.

Some of the banks reportedly facing demands to boost their capital levels include Bank of America Corp, Citigroup Inc, Wells Fargo & Co and Morgan Stanley. GMAC LLC, the former financing arm of ailing carmaker General Motors Corp, is also likely to need another cash injection.

Major banks including JPMorgan Chase & Co and Goldman Sachs Group Inc have reportedly passed the government's stress tests, which are designed to check whether banks have enough resources to survive another dip in the US economy.

According to the results, Bank of America faces a 34-billion- dollar capital shortfall, Wells Fargo needs 15 billion dollars, Citigroup 5 billion dollars and GMAC 11.5 billion dollars, Bloomberg financial news agency reported, citing unnamed sources.

Banks facing a capital shortfall will have until June 8 to present a plan and until November 9 to meet the demands. Some are expected to make up the difference by turning to private investors, while others will have to look for more government support.

Under the plan, banks could be forced to sell ownership stakes to the government, by converting preferred shares already taken by the Obama administration into common stock.

In Bank of America's case this could make the government one of the bank's largest shareholders and may force out chief executive Kenneth Lewis.

White House spokesman Robert Gibbs on Wednesday left open whether some bank executives could be on the chopping block but noted that Obama has "weighed in on changes at the CEO level" in the past.

The administration asked GM chief executive Rick Wagoner to resign earlier this year as part of a deal to continue supporting the country's largest carmaker.

Obama launched the stress tests in February to get a better sense of how banks were managing the current financial crisis. The 19 banks in the stress test were selected for having more than 100 billion dollars in assets. Together, they hold two-thirds of the assets and more than half of the loans in the US banking system.

Some 600 billion dollars have already been invested by the government to keep Wall Street and the US car industry alive. About 100 billion dollars more is left over from a financial rescue package that was approved by Congress in October.

   Bank of America and Citigroup have already received 45 billion dollars in emergency loans from the federal government. Wells Fargo has taken 25 billion dollars.