About 368,000 people filed for initial unemployment benefits in the week ending Saturday, up from a revised 300,000 in the previous week.
Economists believed the earlier figure was artificially low because of the Thanksgiving holiday that week. The initial report of 298,000 claims in the week ended Nov. 30 was only the second time since early 2007 that the number was below 300,000.
But last week's increase exceeded economist forecasts of a rise to about 325,000. The number of claims last week was the highest since the week ended Oct. 5.
The early October jump had come after claims had fallen sharply in previous weeks, when computer upgrade problems in California and Nevada caused those states to under-report their figures.
Claims often surge in the week after Thanksgiving, in part because the holiday falls on a different day each year and makes seasonal adjustments difficult, the Labor Department said.
Government officials and analysts warn of the volatility of the weekly jobless claim figures and say the four-week average is a better gauge, particularly at this time of year.
That figure was 328,750 last week, an increase of 6,000 from the previous week.
Joseph LaVorgna, chief U.S. economist at Deutsche Bank, tweeted Thursday that last week's jump was caused by "seasonal distortions" and he expected the figure to fall back to the four-week moving average level of about 329,000.
Federal Reserve officials are monitoring jobless claims and other economic data as they consider when to start reducing their bond-buying stimulus program.
Analysts said the odds of a reduction at the Fed's meeting next week increased after the government on Friday reported upbeat jobs figures.
The economy added 203,000 net new jobs in November, and the unemployment rate fell to a five-year low of 7 percent, the Labor Department said.