Spanish prime minister Mariano Rajoy said the “credibility of the euro won” in Saturday’s request by his government for as much as €100 billion in European Union aid to restructure the nation’s banks.

Spain will ask for a bank bailout from the eurozone, becoming the fourth and largest country to seek help since the single currency bloc's debt crisis erupted.

Bankia, the fourth largest bank in Spain, could get less than the €19 billion in aid it has asked for, two sources said, prolonging uncertainty surrounding a rescue that has added to fears that Spain itself would need a bailout.

The eurozone should move to a banking union and consider directly recapitalising banks from its permanent bailout fund, the European Commission said in annual economic recommendations that shone a critical light on Spain.