WASHINGTON - The number of U.S. workers filing new claims for jobless benefits rose more than expected last week, pushed up by layoffs in seasonal industries, according to a government report on Thursday that indicated improvement in the labor market would be only gradual.

Initial claims for state unemployment insurance rose 17,000 to a seasonally adjusted 474,000 in the week ended December 5 from 457,000 in the prior week, the Labor Department said. Claims previously had declined for five straight weeks.

Analysts polled by Reuters had forecast claims climbing but only to 460,000. A Labor Department economist said claims had been bumped up by seasonal industries laying people off and by applications that had been held back during the Thanksgiving holiday week.

(Reporting by Lucia Mutikani; Editing by Chizu Nomiyama.)