The number of U.S. people initially applying for unemployment aid last week continued to rise slightly, signaling the labor market recovery is still fragile, the U.S. Labor Department reported Thursday.

The advance figure for seasonally adjusted initial claims for jobless benefits was 372,000 in the week ending on August 18, an increase of 4,000 from the previous week's revised figure.

Meanwhile, the four-week moving average, which helps smooth out week-to-week volatility, also increased to 368,000.

The number of jobless claims below 375,000 generally indicates a sustained drop in the unemployment rate. But the ongoing rise in applications may indicate the hiring is slowing in August.

From April to June, employers only added an average of 75,000 jobs per month, far less than an average of over 220,000 in the first three months this year. But the job growth rebounded in July , with adding 163,000 new jobs.

The advance figure for seasonally adjusted insured unemployment during the week ending on August 11 was 3.317 million, up 4,000 from the prior week.

Though the job growth accelerated in July, the unemployment rate still moved higher to 8.3 percent. In addition, the U.S. economy only expanded at an annual rate of 1.5 percent in the second quarter this year.