ECB chief vows to save euro

European Central Bank head Mario Draghi is raising expectations the central bank might step in and help lower the high borrowing costs that are putting pressure on government finances in Europe.

Draghi said on Thursday in London that the bank would "do whatever it takes to preserve the euro" and added, "believe me, it will be enough."

He discussed the high borrowing costs being imposed on some countries' bonds, saying that "they come within our mandate" - but only if those costs are stopping the ECB's interest rate policies from being implemented throughout the 17-country eurozone.

The ECB has already used similar reasoning to make limited purchases of government bonds in the past with the aim of driving down a government's borrowing costs.

Spain's bond yields have hit record highs recently.