 "European Central Bank president Mario Draghi arrives for a news conference at the ECB headquarters in Frankfurt")
Oil prices also rose, following the rally in equities.
ECB President Mario Draghi's comments on the bank's bond-buying program came as the ECB cut its inflation and growth forecasts for the euro zone, although he said no one on the bank's Governing Council had argued to add to the program now.
That helped to calm some jitters after weeks of market turmoil as investors gauge whether global monetary policy will be kept loose as central banks try to mitigate the recent market turmoil stemming from growing worries about China's economy.
"I think the market is trying to calm down a little bit, with the fear factor reducing somewhat and the data points to a growing U.S. economy," said Peter Cardillo, chief market economist at Rockwell Global Capital in New York.
Friday brings the monthly U.S. jobs report, a key element in the Federal Reserve's decision on when to raise interest rates for the first time in nearly a decade.
The Fed, which meets on Sept. 16-17, has said it will raise rates when it sees sustained economic recovery. While the labor market has strengthened, inflation remains below the Fed's 2 percent target.
With China's stock markets, the root of much of the global volatility in recent weeks, closed on Thursday, European equities markets took the lead.
The FTSEuroFirst leading index of 300 shares was up 2.8 percent, while Germany's DAX shot up 3.2 percent.
The Dow Jones industrial average rose 177.55 points, or 1.09 percent, at 16,528.93. The Standard & Poor's 500 Index was up 23.56 points, or 1.21 percent, at 1,972.42. The Nasdaq Composite Index was up 44.63 points, or 0.94 percent, at 4,794.60.
EURO FALLS
The euro fell, surrendering most of the solid gains put up against the dollar since China devalued the yuan last month, after the ECB outlook.
Against the dollar, the euro >touched a two-week low of $1.1108 during Draghi's news conference and was last off 0.70 percent at $1.1148.
It was as high as $1.1332 earlier this week as investors spooked by the market turmoil in China moved heavily into the euro and yen.
U.S. Treasuries prices rose after the dovish outlook from the ECB made U.S. government debt more attractive than European
counterparts. But caution ahead of Friday's monthly U.S.
employment report limited gains.
Benchmark 10-year Treasury notes were last up 3/32 in price to yield 2.18 percent.
In the energy market, Brent was up $1.38 at $51.88 a barrel, while U.S. crude rose $1.45 to $47.70 a barrel.
