The number of Americans filing new claims for jobless benefits rose a sharper-than-expected 16,000 last week, reflecting temporary layoffs in the factory and service sectors, the Labor Department (search) said on Thursday.

First-time claims for state unemployment insurance benefits (search) rose to 336,000 in the week ended July 9, their highest point since late May, from a revised 320,000 in the prior week, the department said.

Wall Street economists had expected initial claims to rise to just 325,000 from the original reading of 319,000 in the week ended July 2.

A Labor Department analyst said the rise in claims was due to temporary layoffs at carmakers and other manufacturers, as well as seasonal layoffs in the service sector, including school-related jobs.

Analysts say it could be several weeks before the claims data provide a clean read on the health of the job market, largely because summer layoffs at automakers as they ready plants for a new model year often skew the data.

A four-week moving average of claims, which smooths weekly volatility to provide a better sense of the pace of layoffs, rose 250 to 320,750.

A third job-market barometer, the number of unemployed who continued to claim benefits after an initial week of aid, rose 45,000 to 2.62 million in the week ended July 2, the latest for which figures are available.