The ECB, as widely expected, took no new steps on Thursday, but Draghi signaled that it could extend its 1 trillion euro bond-buying quantitative easing program if necessary to combat weak inflation.

"We are ready to act if needed ... and we are open to the full menu of monetary policy," Draghi said at his news conference.

Worries that global economic growth is slowing, particularly in China, have depressed stock and commodity markets across the world in recent months and prompted a series of downgrades to economic forecasts from the International Monetary Fund and others.

Wall Street was higher, gaining ground after the ECB news and earnings reports that included better-than-expected figures from McDonald's Corp (>> McDonald's Corporation) and weak figures from Caterpillar (>> Caterpillar Inc.).

A global index of equities <.MIWD00000PUS> rose 0.8 percent.

The Dow Jones industrial average <.DJI> rose 292.72 points, or 1.71 percent, to 17,461.33, the S&P 500 <.SPX> gained 33.24 points, or 1.65 percent, to 2,052.18 and the Nasdaq Composite <.IXIC> added 74.30 points, or 1.54 percent, to 4,914.41.

The dollar rose 1.3 percent against a basket of currencies <.DXY>. The U.S. unit has been losing ground in the past month as expectations waned for an interest rate hike this year by the Federal Reserve.

The euro fell 1.8 percent after the ECB decision, moving sharply lower after Draghi's comments, trading at $1.1126, a three-week low. It also fell to a one-month low against sterling. Against the yen, the dollar was up 0.5 percent to 120.75 yen .

"Draghi delivered all kinds of dovish signals, which weighed on the euro," said Vassili Serebriakov, currency strategist at BNP Paribas in New York. "He was as dovish as can be without changing policy."

The pan-European FTSEurofirst 300 stocks index <.FTEU3> rose 2.1 percent. An increased full-year sales outlook from Swiss drugmaker Roche (>> Roche Holding Ltd.) helped support the index. The company's shares rose 2.9 percent.

Earlier, MSCI's broadest index of Asia-Pacific shares outside Japan <.MIAPJ0000PUS> slipped 0.2 percent. Japan's Nikkei <.N225> closed down 0.6 percent.

Euro zone government bonds rallied, with benchmark German 10-year Bund yields falling to 0.49 percent, down 0.07 percentage point.

U.S. Treasury yields were little changed, with the 10-year note yield edging up to 2.039 percent.

Oil prices were flat. Brent , the global benchmark, was last up 1 cent at $47.87 a barrel. U.S. crude fell 4 cents to $45.16 a barrel.

Gold held near its lowest in more than a week, last trading at $1,167 an ounce.

(Additional reporting by Hideyuki Sano in Tokyo, Nichola Saminather in Singapore and Nigel Stephenson, Marius Zaharia and Simon Falush in London; Editing by Dave Gregorio and Nick Zieminski)

By David Gaffen