Standard & Poor's carried out a mass downgrade of euro zone countries on Friday, stripping France and Austria of their top-grade AAA ratings in a move that may complicate efforts to solve a two-year old European debt crisis.

Germany, the bloc's largest economy, was spared.

Nine of the 17 members of the euro area had their credit ratings cut by S&P. France and four other countries suffered a one-notch downgrade while Portugal, Italy, Spain and Cyprus were cut by two notches.

S&P reaffirmed the ratings on seven other euro zone countries. The agency said that of the 16 countries reviewed, all save Germany and Slovakia have negative outlooks, meaning more downgrades are possible in the next couple of years.

(Reporting By Walter Brandimarte; Editing by James Dalgleish)