WASHINGTON - The government signaled Friday some distressed banks will need to raise more cash to meet stricter standards it has set for the 19 financial firms that took its "stress tests" and suggested it's ready to step in with more federal help.

Federal Reserve officials held top-secret meetings with bank executives to give them preliminary findings of how each bank would fare if the recession got much worse. It reinforced the Fed's view that major financial firms are "too big to fail," and that the government must do whatever is necessary to save them.

"It appears 'too big to fail' is a fundamental philosophy," said Mark Williams, a finance professor at Boston University and former Fed examiner.

Fed officials told reporters all 19 banks will be required to keep an extra buffer of capital reserves beyond what is required now in case losses continue to mount. That means some banks will likely have to raise additional cash.

But the Fed stressed in a statement that a bank's need for more capital reserves to meet the requirements should not be considered a measure of the "current solvency or viability of the firm."

Senior Fed officials also told reporters regulators will keep a close eye on banks to make sure they have adequate capital to withstand further losses on mortgages and other bad assets as the recession drags on.

The tests of the 19 financial firms, which hold half the loans in the American banking system, are a centerpiece of the Obama administration's financial rescue plan. They were intended to boost confidence in the banking system by giving investors signals about the relative strength of the nation's largest financial firms.

The Fed also is using the results to determine which firms need to raise more money or take other action to strengthen their positions.

The government plans to announce the results of the tests May 4. By law, the banks cannot publicize the results without the government's permission, and the Fed itself offered little new information Friday.