European Central Bank President Mario Draghi signaled the ECB could do more to fight the debt crisis as long as governments push the euro area toward a fiscal union.

"A new fiscal compact" is "definitely the most important element to start restoring credibility," Draghi said in an address to the European Parliament in Brussels today. "Other elements might follow, but the sequencing matters. It is first and foremost important to get a commonly shared fiscal compact right." Draghi didn't specify what more the ECB could do and said the central bank's bond purchases "can only be limited."

Still, he "appeared implicitly to hold up the offer of a significantly higher pace of debt purchases" and "potentially other measures, provided that euro-area governments were to commit to a new fiscal pact," said Julian Callow, chief European economist at Barclays Capital in London.