By Tom Fairless and Paul Hannon 

FRANKFURT -- European Central Bank President Mario Draghi put off a decision on the future of the bank's giant bond-buying program on Thursday, saying officials want to better understand a recent slowdown in the eurozone economy before taking any fresh steps to phase out easy money.

A recent "moderation in growth" across the 19-nation currency union probably reflected temporary factors such as cold weather or the timing of public holidays, Mr. Draghi said at a news conference Thursday. He said, however, taht the slowdown could also reflect more durable weaknesses.

The ECB's decision to stand pat had been expected, but Mr. Draghi's caution suggests the ECB could yet delay a decision to phase out its EUR30 billion ($36.6 billion)-a-month bond-buying program, known as quantitative easing or QE, which is currently due to run at least through September.

Understanding what lies behind the slowdown is "essential for informing our next decisions," Mr. Draghi said. "The very first thing we have to do is place what has happened in the proper context."

The euro settled lower against the dollar at $1.2116, down half a cent on the day. The yield on 10-year German government bonds slid to 0.59%. Yields fall as prices rise.

Analysts said the ECB could delay a decision on the fate of QE until July if economic data remain weak, but that its plans to phase out easy money probably remained intact. The eurozone's economic growth rate for the first quarter will be published on May 2.

"The ECB is largely brushing off concerns about a soft patch in the economy for the moment," said Frederik Ducrozet, an economist with Pictet Wealth Management in Geneva.

With eurozone growth still strong by historical standards, most economists expect the ECB to phase out its bond purchases by December -- four years after the Federal Reserve halted its own QE program -- and to start raising interest rates late next year.

The eurozone economy grew at the fastest pace in a decade during 2017, prompting the central bank to reduce its monetary stimulus by halving its monthly purchases of bonds in January.

However, a raft of recent economic data, from industrial production to retail sales, suggest the eurozone economy slowed in the first quarter of 2018 after outpacing the U.S. economy last year.

Earlier Thursday, Sweden's central bank pushed back a plan to raise interest rates for the first time since 2011, warning that inflation in the largest Nordic economy remains too weak.

The slowdown in the currency bloc comes amid burgeoning risks in the world economy such as currency volatility, rising oil prices and the threat of trade wars.

Mr. Draghi said the slowdown, for now, hadn't fundamentally changed the central bank's expectations for the economy.

But that judgment appears to be provisional, and Mr. Draghi said it was possible the slowdown could mark the start of "a more significant decline."

He said the central bank's rate-setting committee hadn't discussed the future of QE or their key interest rates at their two-day meeting.

The ECB chief also struck a cautious note on trade, warning that "risks related to global factors, including growing protectionism, have become more prominent." He said business confidence had already been weakened by the possibility of higher tariffs.

Write to Tom Fairless at tom.fairless@wsj.com and Paul Hannon at paul.hannon@wsj.com

(END) Dow Jones Newswires

April 26, 2018 12:24 ET (16:24 GMT)