By Brian Blackstone 

WASHINGTON--European Central Bank President Mario Draghi rejected speculation that Greece may be forced to abandon the euro, reiterating that the single eurozone currency is irrevocable.

At a news conference on Saturday during meetings of the International Monetary Fund, Mr. Draghi said he stood by a comment he made in August 2012 that the euro "cannot be reversed."

Mr. Draghi said at the time that "there is no going back to the lira or the drachma or to any other currency. It is pointless to bet against the euro. It is pointless to go short on the euro."

On Saturday, he said he would "say exactly the same words today."

His comments came as concerns have intensified in financial markets that Greece might not be able to come to an agreement with its international creditors to unlock billions of euros in bailout money that Athens needs to repay the IMF and redeem bonds help by the ECB later this year.

If Greece defaults on its debts, that would in turn threaten the country's banks and make it harder for the ECB to approve emergency lending via the Greek central bank.

Mr. Draghi declined to say how the ECB would react to any Greek default, saying: "I don't want even to contemplate" such a scenario.

"We all want Greece to succeed," Mr. Draghi said, adding, "the answer is in the hands of the Greek government."

Turning to the economic outlook, Mr. Draghi said the eurozone economy is on more solid footing than it has been in many years as the region feels the twin effects of lower oil prices and the ECB's stimulus that includes record-low interest rates and a recently launched bond-purchase program.

"The basis for this recovery is broad and stronger than in the past," Mr. Draghi said.

The ECB and IMF have both raised their forecasts for economic growth in the eurozone, which is the world's second-largest economy after the U.S.

Still, despite more favorable trends from Europe, the global economy isn't yet in a phase of robust expansion, he signaled. "I think it's premature to talk about vibrant growth," Mr. Draghi said.