Stocks slid on Thursday as signs of further jobs weakness and an anemic Fed regional survey fueled doubts about prospects for a quick economic recovery.
Investors also worried that Britain's reduced rating outlook might be spur similar actions elsewhere.
U.S. government data showed the number of workers filing new claims for jobless aid fell by 12,000 last week, but ongoing claims rose to a new record as the recession battered employment.
Only time will tell when stabilization turns into growth, but there are a lot of headwinds ... that are going to prevent that growth from emerging, said Dan Greenhaus, market analyst at Miller Tabak & Co in New York.
The Dow Jones industrial average <.DJI> fell 141.45 points, or 1.68 percent, to 8,280.59. The Standard & Poor's 500 Index <.SPX> slid 15.27 points, or 1.69 percent, to 888.20. The Nasdaq Composite Index <.IXIC> dropped 26.99 points, or 1.56 percent, to 1,700.85.
Shares of big manufacturers dropped, with United Technologies Corp
Shares of Exxon Mobil Corp
Investors also pummeled technology shares. Microsoft Corp
The Philadelphia Fed's survey of manufacturing conditions for the U.S. mid-Atlantic contracted in May for the eighth straight month, but improved from April.
The economic data came one day after the U.S. Federal Reserve offered a more pessimistic view for economic recovery, denting optimism that had underpinned the stock market's recent rally from 12-year lows of early March.
Credit ratings agency Standard & Poor's cut its outlook on Britain to negative for the first time, saying government debt could near 100 percent of gross domestic product.
Analysts said the move raised fears of a similar fallout in other countries as governments spend money to spur an economic recovery.
The outlook downgrade of U.K. debt is being taken pretty negatively, said Rick Meckler, president of investment firm LibertyView Capital Management in New York. It sets a precedent for what could start to happen to a lot of the world, given the amount of spending that's going on.
(Reporting by Ellis Mnyandu; additional reporting by Ryan Vlastelica; editing by Jeffrey Benkoe)