The bleak report does not bode well for the economy’s future prospects, economists said. Spending is the primary engine of the economy, accounting for more than two-thirds of gross domestic product. If these pistons start to slow, the system is likely to sputter to a halt. An earlier report on the economy’s performance in the first quarter, released Wednesday by the Commerce Department, showed consumption at its weakest point since the recession of 2001.

Spending is expected to tick up slightly after the government mails out tax rebates in an effort to stimulate the economy. But economists said the coming rebates were unlikely to prop up sales for long.

“The worry is that after that relief fades away, the consumer will still be faced with the same underlying problems,” said Nigel Gault, chief United States economist at Global Insight, a forecasting firm, in a note. “Any burst of spending based on the stimulus payments is likely to prove short-lived.”

Thursday’s report also provided little comfort to the Federal Reserve, which is trying to avoid a recession while keeping price pressures in check. The Fed, in determining inflation dangers, is said to keep close track of a figure in the report that measures prices of goods that exclude energy and food products, which are considered volatile from month to month. This figure, known as the core personal consumption expenditures price deflator, ticked up to 2.1 percent in March from 2 percent in February, slightly above the Fed’s presumed “comfort zone.”

Separate reports on Thursday revealed problems in the construction and manufacturing sectors, which have been battered in the last year by the housing slump. Residential construction fell sharply in March, shrinking 4.6 percent as builders cut back on groundbreakings or stopped work on projects. Over all, spending on construction declined 1.1 percent in March after rising 0.4 percent in February, the Commerce Department said.

Meanwhile, a bellwether gauge of manufacturing activity stayed flat in April as companies laid off workers. The Institute of Supply Management’s index was unchanged at 48.6 last month. Inventories and export orders rose, but new orders stagnated.

Wall Street’s focus turns now to the Labor Department’s report on unemployment in April, which will be released Friday. Economists predict that employers shed up to 100,000 jobs last month, a forecast bolstered by a report on Thursday that claims for unemployment benefits rose by 35,000, to 380,000 last week. Economists had forecast an increase of 18,000.