US stocks kicked off August sharply lower after a round of economic data on Thursday spurred concerns the economy may be slowing faster than anticipated while the Federal Reserve maintains a restrictive monetary policy.

Equities initially opened higher, partly lifted by Meta Platforms after its quarterly results topped expectations and the Facebook parent issued an upbeat outlook for the third quarter.

However, the early gains evaporated after data showed a measure of manufacturing activity from the Institute for Supply Management (ISM) dropped to an eight-month low in July at 46.8, signifying contraction.

"What you’re seeing now, and you will probably see it for the next month or two, is some kind of consolidation and sideways price action," said Bill Strazzullo, chief market strategist at Bell Curve Trading in Boston.

"The bigger picture bull trend is intact ... But we're in a period now where the market is kind of digesting its gains sideways, back and forth."

The S&P 500 lost 75.62 points, or 1.4 percent, to end at 5,446.68, the Nasdaq Composite lost 405.26 points, or 2 .3 percent, to 17,194.14. The Dow Jones Industrial Average fell 494.82 points, or 1.2 percent, to 40,347.97.

August is typically one of the weakest months of the year for stocks.

Other data showed the number of Americans filing new applications for unemployment benefits increased to an 11-month high last week, suggesting some softening in the labour market, although seasonal factors also played a role.

Investors will eye government payroll data later on Friday for signs of further weakness in the labour market. (Reuters)