U.S. gross domestic product (GDP) grew at an annualized rate of 2.4 percent in the fourth quarter of 2013, down from an initial estimate of 3.2 percent. The revision is down to weaker than expected consumer spending. Severe winter weather in the U.S. is expected to slow growth further in the current quarter.

The Commerce Department initially predicted consumer spending had expanded by 3.3 percent, but spending is now estimated to have grown at a 2.6 percent annual rate.

Consumer spending accounts for roughly 70 percent of U.S. economic activity. Bad winter weather has cut into vehicle sales, among other purchases. Despite the revised GDP estimate, U.S. growth should be regarded as strong, the financial information firm Markit said. "The details of the report suggest that investment is growing at an increased rate and underlying demand continued to expand at a reassuringly robust rate, given the headwinds during the closing months of 2013," said Markit Chief Economist Chris Williamson.

Last year, government spending cuts and higher federal taxes squeezed GDP growth. Economists estimate that the contraction in public spending and higher taxes knocked about 1.5 percent from growth last year. The measures were put in place to try to counter soaring budget deficits. Some economists think growth will start to pick up in the spring.

Federal Reserve chair Janet Yellen said on Thursday that the central banking system expected the U.S. economy to strengthen this year, lowering unemployment. The Fed is gradually reducing its monthly bond purchases, in an effort to keep long-term loan rates low and encourage spending and growth. It reduced its original $85 billion monthly bond purchases by $10 billion in December and January in steps, down to a current level of $65 billion.