U.S. stocks closed lower Thursday, snapping the longest winning streaks for the Nasdaq and S&P 500 in two years, as Treasury yields climbed after a disappointing auction of 30-year bonds and comments from Federal Reserve Chair Jerome Powell.

Powell said central bank officials "are not confident" interest rates are high enough to tame inflation, and may not get much more help from improvements in the supply of goods, services and labor.

Stocks had moved slightly lower prior to Powell's comments as yields climbed after a weak auction of $24 billion in 30-year Treasuries with demand for the debt at 2.24 times the bonds on sale. The benchmark 10-year Treasury note yield rose as high as 4.654% on the day.

Powell is "taking a hawkish viewpoint again," said Peter Cardillo, chief market economist at Spartan Capital Securities in New York. "He's reassuring the market that the fight against inflation has not been won a and if economic conditions warrant, they won't hesitate to hike rates again," he said.

"If you add up all the remarks, Powell is telling the market not to get too complacent and that’s putting some pressure on stocks."

Unofficially, the Dow Jones Industrial Average fell 220.59 points, or 0.65%, to 33,891.68, the S&P 500 lost 35.46 points, or 0.81%, to 4,347.32 and the Nasdaq Composite dropped 128.97 points, or 0.94%, to 13,521.45.

Equities have rallied on softening economic data, including the monthly payrolls report, and as U.S. Treasury yields retreated from multi-year highs on the view that the Fed's most recent policy meeting signaled the central bank was done with its rate hike cycle.

After Wall Street's strong rally last week, the pace of gains slowed, and the declines on Thursday snapped an eight-session streak of advances for the S&P 500 and nine-session winning streak for the Nasdaq, the longest for each since November 2021.

Most traders are betting the Fed will keep interest rates unchanged this year, even after Powell's comments, but now see rates cuts starting later in 2024, according to the CME Group's FedWatch Tool.

Several policymakers had already struck a hawkish tone this week to deter rate cut expectations, with some stressing a data-dependent approach to policy.

Meanwhile, a Labor Department report showed jobless claims edged lower last week to 217,000, indicating layoffs have yet to accelerate despite signs of a cooling labor market.

Walt Disney jumped on a quarterly profit beat and as Hollywood actors reached a tentative agreement with major studios.

All 11 of the major S&P sectors were lower, led by declines in healthcare And consumer discretionary with declines of nearly 2% each.

Among other stocks, semiconductor firm Arm Holdings dropped 5% on a downbeat third-quarter sales forecast.