Fitch Ratings has downgraded Greece deeper into junk territory, citing the absence of a new and fully funded financing programme for the country.

Heightened uncertainty surrounding the role of private creditors in any future funding programs from the European Union and the International Monetary Fund also weighed on the decision, as well as Greece's weakening macroeconomic outlook, Fitch said.

The ratings agency cut Greece's rating by four notches to CCC, a rating that implies a substantial risk of default. The new rating was removed from credit watch negative.

A few hours before downgrading Greece, Fitch gave Italy a vote of confidence, saying the country's debt will remain on a sustainable path as long as the government adheres to its "ambitious" fiscal targets.

For Greece, however, austerity measures alone will not be enough.

"New money is required to address Greece's fiscal funding shortfall that would otherwise emerge in 2012," Fitch said in a statement, adding that it expected the EU and the IMF to have decided on the new funds by now.

"While the main parameters of a new multi-annual adjustment program were discussed at an Ecofin meeting on July 11th, no further clarity on the volume and the terms of new money or the nature of private sector participation was forthcoming," it said.

Standard & Poor's already downgraded Greece to CCC one month ago, leaving a negative outlook on the rating. Moody's has the country at Baa1, one notch above its competitors.