WASHINGTON – The economy slowed sharply in the first three months of the year. High gas prices cut into consumer spending, bad weather delayed construction projects and the federal government slashed defense spending by the most in six years.

The 1.8 percent annual growth rate in the January-March quarter was weaker than the 3.1 percent growth in the previous quarter, the Commerce Department reported. And it was the worst showing since last spring, when the European debt crisis slowed growth to a 1.7 percent pace.

Federal Reserve Chairman Ben Bernanke and other economists say the slowdown is a temporary setback. They generally agree that gas prices will stabilize and the economy will grow at a 3 percent pace in each of the next three quarters.

But gas prices are still going up. The housing market has shown little signs of recovering. And lawmakers are proposing some of the steepest cuts in federal spending in a generation. Those cuts would filter down to state and local governments, which are already wrestling with their own budget crises.

“The economy has lost its modest upward momentum, and headwinds such as rising gasoline prices and further budget cuts suggest the recovery will continue at only a moderate pace going forward,” said Sal Guatieri, senior economist at BMO Capital Markets.

The national average for a gallon of gas was $3.88 on Thursday. That’s an increase of 30 cents in the first month of the April-June quarter.

An inflation gauge in the report showed consumer prices rose last quarter at the fastest pace in nearly three years. Most of the increase came from higher fuel costs.

Rising gas prices are draining most of the extra money that Americans are receiving this year from a Social Security payroll tax cut.

That’s a major reason why consumer spending cooled off in the January-March quarter. Consumers boosted spending at a 2.7 percent pace, down from the previous quarter’s 4 percent pace and the weakest since last summer. Consumer spending is important because it accounts for roughly 70 percent of overall economic activity.

“All things considered, it could have been worse,” said economist Paul Dales at Capital Economics. Even though consumers spent less, the pace of spending by historical standards is decent. “Nevertheless, in a quarter when the economy began to benefit from additional monetary and fiscal stimulus, we had originally expected a lot more,” he said.

Pump prices weren’t the only reason spending slowed. Harsh winter weather also kept people from shopping in many parts of the country. Winter also forced builders to delay construction projects, a big factor holding back overall economic activity.