Wall Street was also helped by dollar gains after the European Central Bank kept its benchmark interest rate on hold at a record-low level as President Mario Draghi warned the eurozone recovery remains fragile.
Around 45 minutes into trade, the Dow Jones Industrial Average was down a slight 10.34 points (0.06 percent) to 16,452.40.
The broad-based S&P 500 rose 1.82 (0.10 percent) to 1,839.31, while the tech-rich Nasdaq Composite added 1.32 (0.03 percent) to 4,166.93.
US jobless claims fell last week by 15,000 to 330,000, representing a drop in layoffs that, combined with other recent data on the jobs market suggest a possible upside surprise to December job creation numbers when they are released Friday.
The euro sank against the dollar, dropping sharply from about $1.3627 to below $1.3570 after Draghi acknowledged continuing worries about the threat of deflation in the eurozone, with the ECB pledging decisive action if conditions worsen.
Alcoa shares fell 2.3 percent after the Justice Department announced charges that it bribed Bahrain officials to get business; Alcoa agreed to settle the charges with US agencies for $384 million.
Carrier United Continental gained 11.1 percent after announcing its per-passenger-mile revenue gained strongly in December and that its overall fourth quarter capacity would be up a solid 2.6 percent from 2012.
Biotech firm Intercept Pharmaceuticals rocketed 274 percent after announcing positive results from trials of its treatment for nonalcoholic steatohepatitis (NASH), a leading cause of cirrhosis and liver failure.
Home furnishings retailer Bed Bath and Beyond lost 12.5 percent.
Bond prices rose slightly. The yield on the 10-year US Treasury slipped to 2.98 percent from 2.99 percent Wednesday, while the 30-year fell to 3.89 percent from 3.88 percent. Bond prices and yields move inversely.