Fears that the fragile American economy may be threatened by the financial crisis in Europe gripped Wall Street on Thursday, sending the stock market into sharp decline that left anxious traders wondering where the pain would stop.

The 376-point drop punctuated what amounts to a slow-motion crash that began in late April. The Dow Jones industrial average has now fallen more than 1,000 points in a matter of weeks, signaling what is known as a “correction” — a sort of mini-bear market typically defined as a 10 percent decline in a short period of time.

With Thursday’s sell-off, this broad decline gained momentum and quickly spread beyond stocks to commodities like copper, which are considered economic bellwethers.

The price of oil fell to $69.75 a barrel, down $2.73, or about 4 percent, after having fallen at one point by about 8 percent.

Fixed income investments rose and the yield on the Treasury’s benchmark 10-year note fell to 3.21 percent, down from 3.37 percent late Wednesday and the lowest level this year.

Nagging worries that Europe’s debt crisis will spread, compounded by uncertainties over financial regulation on both sides of the Atlantic, have set investors the world over on edge.

“People are learning to think the unthinkable,” said Willem Buiter, chief economist of Citibank. Many worry that Greece will be unable to pay its debts despite a sweeping rescue effort by the European Union.

At the close, the Dow Jones industrial average was down 376.36 points, or 3.6 percent, at 10,068.01. The Standard & Poor’s 500-stock index was down 43.46 points, or 3.9 percent, at 1,071.59 and the Nasdaq composite was down 94.36 points, or 4.1 percent, at 2,204.01.

Indexes in Europe and Asia were all lower.

New measures in Germany to ban naked short selling, uncertainty over financial regulation in the United States and persistent Euro zone troubles ganged up with Thursday’s disappointing jobless claims and signs of lagging economic indicators to smother any optimism about corporate results or signs of a recovery that might have lifted sentiment.

“There is no sector that is being spared,” said Anthony Conroy, head equity trader at BNY ConvergEx Group. “You have heard the phrase flight to quality? We are having a flight to liquidity. Everybody is trying to get liquid. Gold, oil, silver, financials — every sector is getting hit.”

Jim Dunigan, managing executive of investments for PNC Wealth Management, said the market was plagued by euro zone troubles and uncertainty over financial regulation in the United States.

“When there is that much uncertainty you are not going to get a lot of risk taking,” Mr. Dunigan said. “That clouds the picture of a sustainable recovery in the United States.”

On Thursday, the United States Senate voted to close debate on a financial regulatory bill, putting Congress on path to approving a broad expansion of government oversight of the increasingly complex financial markets that is intended to prevent a repeat of the 2008 economic crisis.

While there have been recent indicators suggesting an economic recovery is under way in the United States, the Labor Department delivered some disappointing figures Thursday for new claims for unemployment benefits, saying they rose by 25,000, to 471,000. Analysts had expected the weekly claims to drop.

A separate report Thursday also showed that a measure of leading economic indicators fell in April. The Conference Board index declined 0.1 percent last month, the first time in more than a year.

But much of the market concern flowed from developments in Europe. “There is a tremendous amount of global uncertainty and that uncertainty is breeding volatility,” said Mr. Conroy. “Over all, the U.S. economy is in pretty good shape. But people want clarity and there is not a whole lot of clarity because of what is going on overseas.”

Howard Silverblatt, the senior index analyst for Standard & Poor’s, said that the uncertainty over how much exposure companies had to the euro was adding to the volatility of United States equities and their issues of profitability, sales and growth. “It raises the risk factor,” he said.

General Electric fell more than 4 percent; Boeing was down about 3 percent and Caterpillar was down 2.4 percent.

Henk Potts, an analyst at Barclays Wealth in London, said there were general fears about a “tsunami” of new financial rules being enacted as a backlash by European policy makers, many of whom are blaming speculators for the rise in yields on euro-zone government bonds.

In the meantime, there are broader doubts about how effective the euro zone’s financial support packages will be in stabilizing markets, reducing debt levels and restoring confidence.

“It’s goodbye financial crisis, hello fiscal crisis,” Mr. Potts said.

Germany is expected to vote on Friday on its contribution to a nearly $1 trillion support package for European countries struggling with debt.

In London, the FTSE 100 was down 1.7 percent and the EuroStoxx 50 index was off 1.8 percent at the close. Both had gained initially, as investors sought bargains after the recent declines. They turned downward after jobless claims in the United States unexpectedly increased, then trimmed some of the losses late in the session.

Earlier, Asian stock markets turned lower as investors brushed off good economic news in the region and focused instead on lingering worries about the debt crisis in Europe.