The number of new US jobless claims filed last week rose sharply by 64,000, partly due to applications for a new government programme extending unemployment benefits for 13 weeks.
The benefits plan is part of an economic stimulus package passed by Congress to help workers who lost their jobs amid last year's recession and in the aftermath of the September 11th attacks.
The US labour department said today first-time jobless claims - a guide to the job market and the pace of layoffs - soared to 460,000 in the week ended March 30th, the highest figure for any week since early December last year. In the previous week, initial claims totalled a revised 396,000.
Economists had expected claims to fall to 376,000 in the March 30th week.
News of the rise in jobless claims took financial markets by surprise, with US Treasury bonds seeing a jump in prices.
More data on the US jobs market are due tomorrow with the release of the March non-farm payrolls report.
US unemployment is expected to edge up to 5.6 per cent from 5.5 per cent in February and outside the farm sector, 41,000 jobs are expected to be created compared with a gain of 66,000 in February.