Draghi was referring to the stubbornly low inflation rate, which touched a five-year low of 0.3%. The ECB has set a 2.0% inflation rate target. Meanwhile, the jobless rate remained at 11.5% in July.

Meanwhile, increased uncertainty fueled safe-haven demand. Specifically, NATO satellite images revealed Russian troop movements in eastern Ukraine, heightening fears of escalating violence. [Treasury ETFs Find Support As Investors Hedge Risk]

iShares 7-10 Year Treasury Bond ETF

For more information on the Treasuries market, visit our Treasury bonds category.

Max Chen contributed to this article.