US stocks ended sharply lower on Tuesday as a profit warning by Walmart dragged down retail shares and exceptionally weak consumer confidence data also fueled fears about spending.

Walmart shares sank after the retailer cut its full-year profit forecast late on Monday. Walmart blamed surging prices for food and fuel, and said it needed to cut prices to pare inventories.

Shares of Target and Amazon also dropped.

Data showed US consumer confidence dropped to nearly a 1-1/2-year low in July amid persistent worries about higher inflation and rising interest rates.

"Walmart basically pulled the plug, and most retailers are lower across the board," said Peter Cardillo, chief market economist at Spartan Capital Securities in New York.

With this week's coming Federal Reserve decision mostly discounted by the market, the focus is on earnings and data, he said.

The Fed started a two-day meeting and on Wednesday, it is expected to announce a 0.75 percentage point interest rate hike to fight inflation. Investors have worried that aggressive interest rate hikes by the Fed could tip the economy into recession.

Amazon, which said it would raise fees for delivery and streaming service Prime in Europe by up to 43 percent a year, was among the biggest drags on the Nasdaq and S&P 500, while consumer discretionary led declines among S&P 500 sectors.

The S&P 500 lost 1.2 percent to end at 3,921, while the Nasdaq Composite lost 1.9 percent to 11,562. The Dow Jones Industrial Average fell 0.7 percent to 31,761.

Meanwhile, Coca-Cola gained after the company raised its full-year revenue forecast. McDonald's rose after beating quarterly expectations.

The International Monetary Fund cut global growth forecasts again. (Reuters)