NEW YORK - US stocks opened higher on Tuesday as better-than-expected China GDP growth in the fourth quarter brightened up to a certain degree the downgrades of several European countries' credit ratings by Standard & Poor's on Friday.

China's economic growth slowed to an annualized 8.9 percent, the slowest pace since mid-2009, although it beat expectations of 8.7 percent. The economic data helped lift the optimism in market.

On the economic front, the Empire State Manufacturing Survey showed manufacturing activity in the New York region picked up in January, from 9.53 to 13.48, the highest level in nine months, keeping in line with the trend of modest improvement in US economic data.

Meanwhile, investors focused on earnings reports. Citigroup posted its fourth-quarter earnings report, with a profit of 1.16 billion dollars, which missed the market expectations.

The Dow Jones industrial average gained 122.49 points, or 0.99 percent, to 12,544.55. The Standard & Poor's 500 was up 11.51 points, or 0.89 percent, to 1,300.54. The Nasdaq Composite Index rose 30.78 points, or 1.14 percent, to 2,741.54.