U.S. jobless claims jumped unexpectedly last week to their highest level since October, suggesting the labor market is still in a rut despite signs of improvement in the economy.

The number of Americans filing for first-time unemployment benefits rose to 445,000 from an upwardly revised reading of 410,000 in the prior week, the Labor Department said on Thursday. It was the biggest one-week jump in about six months, confounding analyst forecasts for a small drop to 405,000.

A Labor Department official noted the rebound occurred following the holidays, which may have hindered reporting of new claims and created a backlog.

Continuing claims retreated sharply to 3.88 million from 4.13 million, a potentially encouraging sign. However, the total number of Americans on benefit rolls, including extended benefits under emergency government programs, jumped to 9.19 million from 8.77 million.

The four-week moving average of new claims, which strips out short-term volatility in the data, rose by 5,500 to 416,500.

The U.S. economy has been expanding since the summer of 2009, but the pace of growth has not been sufficient to put a significant dent in the unemployment rate, which remains at an elevated 9.4 percent.

Unemployment