The European Central Bank chief said Wednesday there is "clear evidence" its stimulus program is boosting the economic fortunes of the 19-nation euro currency bloc.
Bank President Mario Draghi said the eurozone's economy "has gained further momentum" since the end of last year and expects the recovery to "broaden and strengthen substantially."
The bank is in the initial stages of making $1.1 trillion in bond purchases to boost European business activity and cut the eurozone's 11.3 percent jobless rate. Europe's unemployment rate is more than twice as high as in the United States, where a series of larger bond-buying programs helped the world's biggest economy advance from the depths of the 2008 recession.
Draghi said despite Europe's improving economy, the bank would continue its stimulus program through its planned expiration in September 2016.
The eurozone is still facing difficult negotiations with Greece over its bid to ease the financial restrictions imposed on it by international lenders in exchange for billions of dollars in bailouts.
The Standard & Poor's financial services firm downgraded Greece's credit rating Wednesday to so-called junk status, saying it expects the Athens government will not be able to keep its financial commitments without "deep economic reform or further relief."