Updated

The number of Americans filing initial claims (search) for jobless pay grew by more than expected last week, government data showed on Thursday, with seasonal factors offsetting a large drop the week before.

First-time claims for state unemployment benefits rose 40,000 to 349,000 in the week ending July 10, the Labor Department (search) said.

Wall Street analysts had forecast a substantial rise in claims to 346,000 from a revised 309,000 the previous week.

Last week's number, originally reported at 310,000 and much lower than expected, had been heavily influenced by seasonal factors linked to the expected closure of auto plants for an annual exercise to change over to next year's models. Instead, this influence showed up a week later, Labor officials said, possibly because of the timing of the July 4 holiday.

While initial claims rose, the four-week moving average of filings, which smooths weekly fluctuations to provide a better picture of underlying trends, advanced 3,250 to 339,000 from a revised 335,750. This was initially reported at 336,000.

Strong economic growth has delivered a sustained improvement in hiring in the United States, with 671,000 jobs added to the nonfarm payroll (search) between April and June, although June's score of 112,000 new jobs was less than half the number expected.

The number of unemployed on the benefit rolls after claiming an initial week of aid rose by 112,000 to 2.971 million in the week ending July 3, the latest for which figures are available.