By REUTERS

WASHINGTON (Reuters) — Manufacturing slowed in February and consumer spending was flat for a third straight month in January, new economic data showed on Thursday, suggesting the economy lost more momentum than expected early this year.

Other reports on Thursday were more upbeat, with new claims for jobless benefits last week hovering near four-year lows and retailers and automakers reporting brisker February sales.

Nevertheless, the spending and factory data cut into the optimism generated by a recent decline in the unemployment rate, and suggested rising energy prices were taking a toll.

The Commerce Department said inflation and taxes reduced income gains in January, and inflation-adjusted spending was unchanged for the third consecutive month.

“Consumer spending is off to a pretty weak start,” said Keith Hembre, an economist at Nuveen Asset Management in Minneapolis. Mr. Hembre said the data painted “a pretty weak picture for first-quarter G.D.P. despite the strong jobs numbers.”

Consumer spending and the restocking of company shelves lifted economic growth to a 3 percent annual rate in the last three months of 2011, its quickest rate in more than a year.

Economists think growth slowed early this year, and TD Securities lowered its first-quarter forecast to a 1.5 percent rate from 1.9 percent, citing the data on consumer spending.

The Institute for Supply Management said its national factory index dropped to 52.4 last month, indicating a slower rate of expansion. Most analysts had expected the index to rise, and the reading was below the lowest forecast in a Reuters survey.

Analysts said a surge in the institute’s reading of prices paid showed factories were being hurt by oil prices, which have risen on tensions between Iran and the West over Tehran’s nuclear ambitions.

The recent rise in energy prices is likely to lead the list of concerns for producers in the coming months, a Barclays analyst, Peter Newland, said.

The Commerce Department said its gauge of inflation rose 0.2 percent in January, picking up a bit from December as energy prices posted their first increase in four months. Economists expect rising gasoline prices were even more troublesome in February.

Despite higher costs at the pump, a surprising sales gain by General Motors and strong performances by Ford Motor and others pushed auto sales close to a four-year high in February.

Reports from retailers offered another sign January’s spending weakness might be temporary. Chain stores sales rose 6.7 percent in February from a year earlier, according to the International Council of Shopping Centers.

The drop in jobless claims also buttressed the view that the economic recovery was still firmly entrenched, and it suggested a government report next week would show companies were still hiring at a brisk pace in February.

The number of people receiving benefits under regular state programs after an initial week of aid fell in mid-February to the lowest level since August 2008.

“It’s consistent with our thought that the pace of job growth is picking up and accelerating,” Kevin Cummins, an economist at UBS Securities in Stamford, Conn., said.