WASHINGTON  President Obama branded Wall Street bankers “shameful” on Thursday for giving themselves nearly $20 billion in bonuses as the economy was deteriorating and the government was spending billions to bail out some of the nation’s most prominent financial institutions.

“There will be time for them to make profits, and there will be time for them to get bonuses,” Mr. Obama said during an appearance in the Oval Office with Treasury Secretary Timothy F. Geithner. “Now’s not that time. And that’s a message that I intend to send directly to them, I expect Secretary Geithner to send to them.”

It was a pointed  if calculated  flash of anger from the president, who frequently railed against excesses in executive compensation on the campaign trail. He struck his populist tone as he confronted the possibility of having to ask Congress for additional large sums of money, beyond the $700 billion already authorized, to prop up the financial system, even as he pushes Congress to move quickly on a separate economic stimulus package that could cost taxpayers as much as $900 billion.

This week alone, American companies reported as many as 65,000 job cuts, and public anger is rising over reports of profligate spending by banks and investment firms that are receiving help from the $700 billion bailout fund. About half of that money is still available, but the new administration has yet to announce how it will use it, and many analysts think it will take far more to stabilize the banking system.