The number of U.S. workers filing new claims for jobless benefits unexpectedly soared last week as applications held back during the Easter holiday were processed, government data showed on Thursday.

Initial claims for state unemployment benefits rose 24,000 -- the largest increase in two months -- to a seasonally adjusted 484,000, the Labor Department said.

Analysts polled by Reuters had expected claims to dip to 440,000 from 460,000 the prior week, a number that was unrevised in Thursday's report.

A Labor Department official said the increase in claims last week was mainly due to administrative factors rather than economic ones. I don't think there is a whole lot of layoffs going on, he said.

The four-week moving average of new claims, which irons out week-to-week volatility, rose 7,500 to 457,750.

(Reporting by Lucia Mutikani; Editing by Chizu Nomiyama)