Standard & Poor's Cuts Credit Ratings for Nine Euro Zone Nations

"Today's rating actions are primarily driven by our assessment that the policy initiatives that have been taken by European policy makers in recent weeks may be insufficient to fully address ongoing systemic stresses in the euro zone," S&P said in a press release announcing the downgrade.

In a potentially more ominous setback, talks broke down between Greece and its creditors over a debt swap seen as crucial to avert a Greek default, although officials said more talks are likely next week.

If Greece cannot persuade banks and insurers to accept voluntary losses on their bond holdings, a second international rescue package for the euro zone's most heavily indebted state will unravel, raising the prospect of bankruptcy in late March, when it has to redeem 14.4 billion euros in maturing debt.

S&P lowered its long-term rating on Cyprus, Italy, Portugal and Spain by two notches, and cut its rating on Austria, France, Malta, Slovakia and Slovenia by one notch.

The move puts highly indebted Italy on the same BBB+ level as Kazakhstan and pushes Portugal into junk status.

The credit-rating agency affirmed the current long-term ratings for Belgium, Estonia, Finland, Germany, Ireland, Luxembourg and the Netherlands.