The number of Americans initially applying for unemployment aid last week surged to the highest level in five weeks after a moderate decline a week earlier, the U.S. Labor Department reported Thursday.

The advance figure for seasonally adjusted initial claims for jobless benefits was 383,000 in the week ending May 26, an increase of 10,000 from the previous week's revised figure.

The number of jobless claims has to stay below 375,000 to indicate a sustained drop in the unemployment rate. Meanwhile, the four-week moving average, which helps smooth out week-to-week volatility, increased for the first time in a month to 374,500.

Economists point out that the volatility of applications suggests that the U.S. labor market recovery is still fragile and job growth needs to be accelerated.

The advance figure for seasonally adjusted insured unemployment during the week ending May 19 was 3.242 million, down 36,000 from the prior week.

In addition, U.S. economic growth slowed to an annualized pace of 1.9 percent in the first quarter of the year, down from the initial estimate of 2.2 percent, according to revised figures released Thursday by the Commerce Department.