The number of Americans filing new claims for unemployment benefits last week rose to the highest level since September, but the underlying trend remained consistent with a firming labor market.

Initial claims for state unemployment benefits increased 21,000 to a seasonally adjusted 313,000 for the week ended Nov. 22, the Labor Department said on Wednesday. It was the first-time since early September that claims broke above the 300,000 threshold.

The four-week moving average of claims, considered a better measure of labor market trends as it irons out week-to-week volatility, remained below 300,000 for an 11th straight week, a sign that the jobs market was improving.

Economists polled by Reuters had forecast claims falling to 288,000 last week. A Labor Department analyst said there were no special factors influencing last week's claims data.

The claims report showed the number of people still receiving benefits after an initial week of aid fell 17,000 to 2.32 million in the week ended Nov. 15, the lowest since December 2000.

The so-called continuing claims covered the household survey week from which the unemployment rate for November will be calculated.

Continuing claims fell 71,000 between the October and November survey period, suggesting the unemployment rate could fall from a six-year low of 5.8 percent.