WASHINGTON - May 5, 2011 - The number of Americans applying for unemployment benefits surged last week to the highest level in eight months, a troubling sign a day ahead of the government's report on April employment.

The Labor Department said Thursday that the 43,000 spike in applications to a seasonally adjusted 474,000 last week was largely the result of unusual factors, including a high number of school systems in New York that closed for spring break.

Still, it marked the third increase in four weeks. The four-week average, a less volatile measure, rose for the fourth straight week to 431,250. Applications have jumped 89,000, or 23%, in the past four weeks.

"The trend is clearly upward, so that's disconcerting," said Kurt Karl, chief U.S. economist for Swiss Re. "When you get three or four weeks in a row of special factors, they're no longer so special."

Applications near 375,000 are typically consistent with sustainable job growth. Weekly applications peaked during the Depression at 659,000.

Rising unemployment applications and other weak economic data this week have prompted some analysts to worry that higher fuel prices may be causing employers to slow their pace of hiring.