Asked at a news conference on Thursday why the ECB had not decided on a more broad-based programme of asset purchases, Draghi said of plans outlined: "We think it's a significant package. Are we finished? The answer is no! We aren't finished here. If need be, within our mandate, we aren't finished here."

Draghi also said in the statement he read out at the start of his news conference that the bank was ready to take more action if necessary.

"If required, we will act swiftly with further monetary policy easing. The Governing Council is unanimous in its commitment to using also unconventional instruments within its mandate should it become necessary to further address risks of too prolonged a period of low inflation," he said.

(Reporting by Eva Taylor; Editing by Hugh Lawson and Ruth Pitchford)