At 1500 GMT the Dow Jones Industrial Average was up 73.91 points (0.61 percent) to 12,159.93.

The broader S&P 500 rose 8.83 (0.68 percent) to 1,306.37, while the tech-centric Nasdaq Composite added 25.12 (0.93 percent) to 2,723.42.

The market appeared to shrug off negative news from elsewhere, including China's struggle to slow its economy, Japan's post-quake woes, the fall of Portugal's government and warnings about the US long-term fiscal deficit, said analysts at Briefing.com.

"The hits keep coming, yet the US stock market is still standing," they said.

Government data before the market opened showed a continuing decrease in applications for unemployment insurance, a sign that the labor market continues to improve, though still at a slow pace.

New jobless claims fell to 382,000 in the week ending March 19, the Labor Department said, down from 387,000 the week before, sustaining a downward trend that began in August.

At the same time, Commerce Department data showed a significant 0.9 percent fall in US factory orders in February, against expectations of an increase from the low January figures.

Lower demand for machinery and often volatile orders for defense equipment prompted the fall, the Commerce Department said.

"Bottom line is that this does not look good," said Ian Shepherdson of High Frequency Economics, adding that lingering weather effects or statistical anomalies may yet be to blame.

Shares of electronics retailer Best Buy jumped four percent on the opening after better-than-expected earnings, but fell back for a 2.2 percent loss after the company gave a cloudy forecast for 2012 amid tough competition from on-line sellers and other big-box chain stores.

The bond market opened lower. The yield on the 10-year Treasury rose to 3.37 percent from 3.35 percent late Wednesday, while that for the 30 year note moved to 4.46 percent from 4.45 percent.

Bond prices and yields move in opposite directions.