The European Commission has noted that "there is a lot of oil around" inside reserves in EU countries even if Iran makes good on threats to stop shipments next week.

Besides a treaty on fiscal discipline, European leaders meeting in Brussels on Monday will also seek to adopt non-binding measures on employment. Their summit will come in the midst of a general strike expected to paralyse the EU capital.

Germany's Merkel has rejected calls for an increase in the size of the eurozone's bail-out fund and called for more powers to be transferred to EU institutions as a way of overcoming the crisis.

EU countries on the UN Security Council and a handful of Arab states have put forward a new resolution on Syria. But Russia is unlikely to let it fly.

EU finance ministers have warned Hungary it may lose EU funds if it fails to fix its excessive deficit. Meanwhile, Prime Minister Viktor Orban met EU officials in Brussels to discuss the ongoing row over changes to Hungary's domestic laws.