The Fitch ratings agency has downgraded Greece's long-term credit rating further into junk status, in yet another blow to the debt-ridden country.

Fitch downgraded Greece on Friday to B+ from BB+, citing problems with the country's implementation of essential reforms to its economy.

It said the move "reflects the scale of the challenge facing Greece in implementing a radical fiscal and structural reform programme necessary to secure solvency of the state and the foundations for sustained economic recovery."