Fitch Ratings has upgraded Greece's credit rating from CCC to B-, a one-notch improvement that still leaves the bonds issued by the crisis-battered country well below investment grade.

The ratings agency says the outlook of the Greek economy is positive and it expects talks with the country's international creditors to be concluded "without creating instability."

A Fitch statement adds that other European countries using the euro currency are expected to grant Greece substantial debt relief next year. It says that will boost market confidence and help Greece finance itself directly by issuing bonds after its current bailout program ends in a year.

Fitch said late Friday that Greece's political situation has become more stable and there is "limited" risk of a future government reversing bailout-linked austerity and reforms.