Mr. Draghi’s call for government action, which he said had the unanimous support of the bank’s 25-member Governing Council, was also an expression of unity with his soon-to-be-successor, Christine Lagarde. Ms. Lagarde, who will become the European Central Bank’s president in November, issued a similar plea when she spoke to members of the European Parliament last week.

For much of the last decade, the European Central Bank has prevented the eurozone economy from collapsing with an array of sometimes unprecedented crisis measures. But economic growth has almost stalled, and there is a growing consensus among analysts that wealthier countries like Germany or the Netherlands need to pump money into their economies, and by extension the rest of the eurozone, with tax cuts or public works projects.

Central banks are “not the only game in town,” Ms. Lagarde said at the European Parliament last week.

Read more: Central banks around the world are cutting rates to fend off recession.

The measures that the European Central Bank announced Thursday go beyond what many analysts were expecting. Recent comments by members of the Governing Council had cast doubt on whether the bank would restart purchases of government and corporate bonds. It has been only nine months since the bank ended a previous bond-buying program, an initiative that started in the midst of the financial crisis.

The bank will buy 20 billion euros’ worth of bonds, or $22 billion, every month starting in November, a form of money printing intended to inject money into the system and hold down interest rates.