The number of Americans initially applying for unemployment aid rose up last week, showing a slow and fluctuating improvement in the labor market, the Labor Department reported Thursday. The advance figure for seasonally adjusted initial claims for jobless benefits was 354,000 in the week ending May 25, up 10,000 from the upward revised figure the previous week. In the past month the weekly reading fell twice and rose twice. As a result, the four-week moving average, which helps smooth out week-to-week volatility, edged up to 347,250 from 340,500 the previous week. It remained below 375,000, which generally indicates a sustained drop in the unemployment rate. The advance figure for seasonally adjusted insured unemployment during the week ending May 18 stood at 2.986 million, up 63,000 from the previous week. U.S. Commerce Department said Thursday that the economy rose at a 2.4 percent annualized rate compared with the 2.5 percent pace initially reported. Some observers say the unemployment problem is not due to much firing but a lack of hiring. In April, the U.S. unemployment rate dropped to 7.5 percent with total non-farm payroll employment increasing by 165,000. The U.S. Labor Department is expected to update the unemployment figure next week.