The United States has been in recession since December 2007, but most economists expect the downturn to end in the second half of the year.

A regional survey issued Wednesday by the Federal Reserve found that nearly all regions of the country reported their economies were stabilised or growing, but it warned that most regions were still experiencing 'flat' retail sales and 'weak' labour markets.

Obama's key measure to revive the economy was a $787-billion stimulus package that was narrowly approved by Congress in February.