A leading credit ratings agency says it is cautiously optimistic that the worst of Europe's debt crisis is over and that the euro will remain intact.

Fitch Ratings said Tuesday that the group of 17 European Union countries that use the euro is showing signs of improvement in key areas such as competitiveness and that the peak of the austerity measures, even in Greece, may have passed.

However, Douglas Renwick, senior director of Fitch's European sovereign credit analysis, says a full recovery from the crisis will take most of this decade and that there is a potential for further market volatility this year due to, among others, general elections in Italy and Germany, and a lack of economic growth in Europe.