Moody's Investors Service on Thursday raised its U.S. sovereign outlook to stable from negative and affirmed its blue-chip Aaa rating for the country, noting the resilience of the economy.

The economy is growing moderately, but it is still "progressing at a faster rate compared with several Aaa peers and has demonstrated a degree of resilience to major reductions in the growth of government spending," Moody's said in a statement.

The Moody's affirmation comes as the budget outlook for the world's largest economy has brightened.

Earlier this month, for example, the White House slashed its estimate of the current year's fiscal deficit to $759 billion, or 4.7 percent of GDP, from its April forecast of $973 billion.

"We feel that we have enough information on the debt trajectory at this point to make a conclusion even without information on any possible further actions in Washington," said Steven Hess, Moody's lead U.S. sovereign credit analyst.

(Read more: US bond prices fall on upbeat factory, jobs data)



Last month Fitch also affirmed the U.S. sovereign AAA rating. But that agency kept a negative outlook, saying still-elevated debt levels leave the country vulnerable to shocks without more deficit reduction.



Standard & Poor's rates the country AA-plus, with a stable outlook.

The upgrade came almost simultaneously with Detroit filing for Chapter 9 bankruptcy protection as the Motor City is saddled with up to $20 billion in long-term debt.



(Read more: Detroit becomes largest US city to file for bankruptcy)