NEW YORK -- The National Bureau of Economic Research panel said Monday the U.S. economy fell into a recession last year.

Recession Definition

The NBER said its group of academic economists who determine business cycles met and decided that the U.S. recession began in December 2007.

Meanwhile, President George W. Bush expressed remorse that the global financial crisis has cost jobs and damaged retirement accounts.

The president told ABC's "World News" in an interview that he will support additional federal intervention, if necessary, to ease the recession. The interview will air Monday night.

Bush told the network: "I'm sorry it's happening, of course."

According to CNN, the nonprofit, nonpartisan NBER is the official source to determine when U.S. recessions begin and end.

Many economists believe the current downturn will last until the middle of 2009 and will be the most severe slump since the 1981-82 recession.

Stocks Fall Sharply Amid Dour Economic News

Stocks plunged on Wall Street amid a pair of downbeat economic reports. The Dow lost a staggering 679 points on Monday.

Investors were already selling stocks lower on concerns about the holiday shopping season before the Institute for Supply Management, a trade group of purchasing executives, said its index of manufacturing activity fell to a 26-year low in November.

The reading of 36.2 from the Institute for Supply Management's monthly survey of manufacturing activity is below October's 38.9. It is also worse than Wall Street economists' expectations of 38.4 as measured by a survey by Thomson Reuters.

A reading below 50 indicates the sector is contracting.

The ISM said the November figure is the lowest since May 1982 when the economy was in the midst of a painful recession.

At the same time, the Commerce Department said construction spending fell by 1.2 percent in October, much bigger than the 0.9 percent decline that many analysts had expected.

The weakness was led by another sizable drop in home construction, which has fallen every month but two over the past 2½ years. Nonresidential building also weakened as developers face tougher times getting financing because the banking system is going through a severe credit squeeze.

Both the housing and manufacturing sectors have been suffering for some time, so the reports were ultimately unsurprising. Wall Street is concerned that consumers, by curtailing their spending further, won't be able to help lift the economy from its slump.

The market is coming off last week's strong performance, amid indications that the start of the holiday shopping season went better than expected for retailers.