Greece financial analysts and local media raised doubts on Friday over the latest "surprise" downgrade of Greece's credit rating from B- to CCC by international ratings agency Fitch.

The agency's experts cited the "increased risk" of a Greek default and exit from the eurozone, after Greek leaders failed to form a government following the May 6 national polls.

As a caretaker government took office on Thursday to lead the country to new polls in June, uncertainty has increased over the implementation of a stability and growth program to overcome the Greek debt crisis.

Financial daily Imerissia called the downgrade a "new negative surprise by credit rating agencies," because just two months ago Fitch had upgraded the country, after a Greek state debt swap plan eased its debt burden.

"This development proves that the downtrend in the Greek stock market over the past week, reflected a widespread anxiety over the political environment, hiding in a sense one more negative development for Greek economy," said Kostas Manolidis in newspaper Proto Thema.

Analysts at Piraeus Securities said the new downgrade by Fitch "further deteriorates a negative climate for Greek economy, raising doubts for potential investors, as long as political uncertainty continues."

Financial news portal "Euro2day" commented, "Perhaps there should be a code of ethics for credit ratings agencies ... Maybe there should be some basic rules for credit ratings assessments."