Europe’s economic commissioner says that neither Italy nor Spain will need need an international bailout to solve their economic woes.

European Union Economic Affairs Commissioner Olli Rehn said Friday he does not think that the continent’s third and fourth largest economies will follow in the footsteps of the debt-ridden governments of Greece, Ireland and Portugal, all of which have had to secure billions of dollars in outside assistance in the last year.

But Rehn said Italy and Spain must strictly implement austerity measures they have adopted to raise taxes and cut spending.

Both countries have faced record borrowing costs this week to finance their government operations as investor fears mounted that they would be the next countries to need bailouts. Interest rates on government bonds increase when investors worry that the debts might not be repaid, which in turn makes it more costly for governments to borrow money.

Rehn said the EU is working “night and day” to craft a plan to stem the continent’s debt contagion. He said details of a financing plan approved last month by European leaders would be set “in weeks, not months.”

European markets have been roiled this week in part by the concern over Italy and Spain, two of the 17 countries that employ the euro currency. But Rehn said investors should not underestimate “the political will” of European leaders to defend the euro.