New claims for US unemployment insurance benefits fell last week after a strong surge in the prior week, official data showed Thursday. Initial jobless claims fell to 434,000 in the week ending May 7, the Labor Department said, according to seasonally adjusted data. The prior week's number was revised to 478,00, an increase of 4,000. The four-week moving average of claims, which helps to smooth week-to-week volatility, rose by 4,500 to 436,750. The Labor Department's seasonal adjustments were skewed this year by the Easter holiday, which fell on April 24, the latest date since World War II. A Labor official said the claims numbers for the first week of May were impacted by spikes in unemployment caused by a tornado in Alabama and, in Virginia, a computer network problem that held up data transmission for the state. The unemployment rate rose to 9.0 % in April after four months of declines.