WASHINGTON -The number of U.S. workers filing new applications for unemployment insurance fell slightly less than expected last week, government data showed on Thursday, implying only a gradual labor market improvement.

Initial claims for state unemployment benefits dropped 11,000 to a seasonally adjusted 448,000 in the week ended April 24, the Labor Department said.

Analysts polled by Reuters had expected claims to fall to 445,000 from the previously reported 456,000, which was modestly revised up to 459,000 in Thursday's report.

The four-week moving average of new claims, which irons out week-to-week volatility, rose 1,500 to 462,500, increasing for a fourth straight week.

Though initial claims have resumed their downward trend interrupted by the Easter holiday, analysts worry the pace is too slow and underscores the fragility of private hiring.

Private hiring last month handed the economy its largest jobs gain in three years. Both claims and the four-week average remain perched above 400,000, a level that analysts associate with labor market stability. Employers are still believed to have added jobs this month.

The number of people still receiving benefits after an initial week of aid fell 18,000 to 4.65 million in the week ended April 17, the Labor Department said. This was a touch above market expectations for 4.62 million.

The so-called continuing claims data covered the household survey week from which the national unemployment rate is derived. Analysts anticipate data will show the unemployment rate was unchanged at 9.7 percent in April.

The insured unemployment rate, which measures the percentage of the insured labor force that is jobless, was unchanged at 3.6 percent in the week ended April 17, the Labor Department said. (Reporting by Lucia Mutikani; Editing by Andrea Ricci)