The productivity of U.S. workers slowed in the first quarter and labor costs rose as a growing economy prompted companies to boost employment, another report from the Labor Department showed today.

The measure of employee output per hour increased at a 1.6% annual rate, after a 2.9% gain in the prior three months. Expenses per employee climbed at a 1% rate after dropping 1%.

The four-week moving average for jobless claims, a less- volatile measure, rose to 431,250 from 409,000.

The number of people continuing to collect jobless benefits rose by 74,000 in the week ended April 23 to 3.73 million. The continuing claims figure does not include the number of workers receiving extended benefits under federal programs.

Extended Benefits

Those who've used up their traditional benefits and are now collecting emergency and extended payments decreased by about 42,900 to 4.12 million in the week ended April 16.

The unemployment rate among people eligible for benefits, which tends to track the jobless rate, rose to 3% in the week ended April 23 from 2.9%, today's report showed. Twenty states and territories reported an increase in claims, while 33 had a decrease.

Initial jobless claims reflect weekly firings and tend to fall as job growth-measured by the monthly non-farm payrolls report-accelerates. These data are reported with a one-week lag.

Employers announced fewer job cuts in April than the same month last year, Chicago-based Challenger, Gray & Christmas Inc. said yesterday. Planned firings decreased 4.8% to 36,490 last month from April 2010.

'Signs of Improvement'