WASHINGTON — Badgered by lawmakers, former Federal Reserve Chairman Alan Greenspan yesterday denied the nation's economic crisis was his fault but conceded the meltdown had revealed a flaw in a lifetime of economic thinking and left him in a "state of shocked disbelief."

Greenspan, who stepped down in 2006, called the banking and housing chaos a "once-in-a-century credit tsunami" that led to a breakdown in how the free market system functions. And he warned that things would get worse before they get better, with rising unemployment and no stabilization in housing prices for "many months."

Gloomy economic reports backed him up. New jobless claims soared to just under 500,000 for last week, and Goldman Sachs, Chrysler and Xerox all said they were cutting thousands more workers. On Wall Street, the Dow Jones industrials bounced erratically before finishing up 172 points — after a two-day drop of nearly 750.

The financial crisis even prompted the Republican Greenspan, a staunch believer in free markets, to propose that government consider tougher regulations, including requiring financial firms that package mortgages into securities to keep a portion as a check on quality.

He said other regulatory changes should be considered, too, in such areas as fraud.

Also looking for solutions, another banking regulator said the government was working on a loan-guarantee plan that could help many homeowners escape foreclosure as part of the $700 billion bailout legislation. That plan is being discussed by the Treasury Department and the Federal Deposit Insurance Corp., said FDIC Chairman Sheila Bair.

Greenspan's interrogation by the House Oversight Committee was a far cry from his 18 1/2 years as Fed chairman, when he presided over the longest economic boom in the country's history. He was viewed as a free-market icon on Wall Street and held in respect bordering on awe by most members of Congress.

Not now. At an often contentious four-hour hearing, Greenspan, former Treasury Secretary John Snow and Securities and Exchange Commission Chairman Christopher Cox were accused by Democrats of pursuing an anti-regulation agenda that set the stage for the biggest financial crisis in 70 years.