NEW YORK (CNN/Money) - The number of Americans filing for unemployment benefits for the first time rose unexpectedly last week as the level of U.S. workers receiving benefits for a week or more hit its highest level in more than 20 years, the government said Thursday.

The Labor Department said the number of Americans filing new claims for unemployment benefits rose to 439,000 in the week ended July 5, from 434,000 the prior week.

Economists, on average, expected 420,000 new claims, according to Briefing.com. A level above 400,000 indicates a stagnant labor market.

Continued claims, the number of people out of work for a week or more, climbed to 3.81 million for the week ended June 28 from a revised 3.73 million the prior week. Last week's figures are the highest since it hit 3.87 million in Feb. 26, 1983.

The four-week moving average of new claims, which smoothes out the weekly fluctuations, rose slightly to 426,750 from 425,750 the prior week.