Stiglitz blamed the policies of President George W. Bush for the US economy's failure to recover.

"The recovery is fragile, we had several years of weak economy and normally after that, you have strong growth," said Stiglitz, a former chief economist at the World Bank and former adviser to president Bill Clinton who supports Democratic candidate John Kerry.

"With the oil prices going up, it takes money out of the economy, it's going to Saudi Arabia. We have this uncertainty about oil prices to which we have contributed by our mismanagement of the situation in the Middle East," he said.

Stiglitz derided Bush's economic policies, saying "his whole program could be summarized in 'more tax cuts for the rich'," adding that Kerry would focus more on tax cuts for poor and middle-income Americans.