European Central Bank head Mario Draghi says the euro currency union remains "incomplete" and needs to be strengthened with better oversight of member countries' economic policies.

Draghi said in the text of a speech Thursday in Helsinki that "for all its resilience, our union is still incomplete."

He said the 18 member countries have agreed not to bail each other out through fiscal transfers — so they need other ways of keeping problems in one country from affecting them all. He called for "joint sovereignty" over economic policies and urged tougher use of the EU's annual review of national budgets.

EU officials are currently reviewing those budgets. They are due to decide before the end of the month whether to ask countries like France and Italy to make more cuts.