"Although further reductions ... are certainly feasible, at this point the scope for using conventional interest rate policies to support the economy is obviously limited," Bernanke said in a speech to business executives in Austin, Texas. The Fed is widely expected to cut a key interest rate when officials next meet on Dec. 15-16.

Treasury Secretary Henry Paulson said the Bush administration is looking for more ways to tap a $700 billion financial rescue program and will consult with Congress and the incoming administration of President-elect Barack Obama.

"While we are making progress, the journey ahead will continue to be a difficult one," Paulson said in a speech to business executives in Washington. "But I have confidence that we are pursuing the right strategy to stabilize the financial system and support the flow of credit into our economy."

In his remarks Monday, Paulson did not provide specifics on what type of programs the administration had under consideration other than to say that it was looking at ways to boost capital into financial institutions.

Asked about the NBER panel's decision that the U.S. fell into a recession in December 2007, Paulson said that he didn't think that decision was going to be "big news" to Americans who have been dealing with the slowdown for some time.

He said that a year ago, the administration could see that the economy was slowing significantly and that officials had moved very quickly to respond to the challenges, an apparent reference to the $168 billion economic stimulus plan that Paulson helped push through Congress last February.

Two new reports provided a grim snapshot of how steep the economic slump is becoming. The Commerce Department reported Monday that construction spending fell by a larger-than-expected 1.2 percent in October, while the Institute for Supply Management said its gauge of manufacturing activity dropped to a 26-year low in November.

The GDP contracted by 0.2 percent at an annual rate in the fourth quarter of 2007, but that that drop was followed growth in the first two quarters of this year, partially boosted by the distribution of millions of economic stimulus payments.

However, employment, one of the measurements tracked by the NBER, has been falling since January.

The NBER decision means that the economic expansion lasted from November 2001 until December 2007. Economic expansions peak and recessions begin in the same month, according to the NBER's dating methods. Founded in 1920, the NBER has more than 1,000 university professors and researchers who act as bureau associates, studying how the economy works.

The decision on the recession means that during the eight years that Bush has been in office, the country has seen two recessions. The first downturn lasted from March 2001 until November of that year.