The overall US unemployment rate has also now risen from 8.9 per cent to 9.4 per cent, the highest level since August 1983.

Earlier this week Barack Obama, the US president, warned it was "pretty clear" that the US unemployment rate was going to rise above 10 per cent and that it would take time for an economic recovery to translate into job growth.

Exports slump

Consumer spending, which fuels two-thirds of US economic activity, increased at a downwardly revised 1.4 per cent rate instead of the 1.5 per cent previously estimated.

In other poor data, exports plunged at a 30.6 per cent rate in the first financial quarter of 2009 instead of the 28.7 per cent estimated a month ago - the steepest drop in foreign sales in 40 years.

The commerce department said the drop had cut 4.16 percentage points from the country's GDP.

In addition, imports dropped at a 36.4 per cent rate, the steepest since the summer of 1947, while overall business investment plunged at a record 37.3 per cent rate during the first quarter.

Spending on new homes construction also fell 38.8 per cent - its biggest fall since 1980.

The US economy is struggling to pull itself out of recession following turmoil in the financial markets, bank collapses and the subprime mortgage crisis.