European Central Bank President Mario Draghi's bond-buying proposal involves unlimited purchases of government debt that will be sterilized to assuage concerns about printing money, two central bank officials briefed on the plan said.

Under the blueprint, which may be called "Monetary Outright Transactions," the ECB would refrain from setting a public cap on yields, according to the people, and a third official, who spoke on condition of anonymity. The plan will only focus on government bonds rather than a broader range of assets and will target short-dated maturities of up to about three years, two of the people said.

The euro jumped half a cent on the report to $1.2596 and European stocks advanced. An ECB spokesman referred to an Aug. 20 statement in which the Frankfurt-based central bank said it was misleading to report on decisions that haven't been taken yet.