First-time claims for unemployment benefits rose by 15,000 last week, driven by the lingering impact of Hurricane Ike on the job market, the Labor Department reported Thursday.

The gains boosted initial jobless claims to 478,000 for the week ending Oct. 18, the report said. The four-week moving average fell by 4,500, down from a seven-year high of 484,750 the previous week.

New York, Michigan and Florida saw the largest increases in new claims, with sharp upturns attributed to layoffs in the construction, automotive and service sectors.

Earlier this week, the Labor Department reported over 2,000 mass layoffs by employers nationwide last month, the most since the Sept. 11 terrorist attacks.