Athens - Moody's said late on Friday that it was placing Greece's government bond rating of Caa1 on review for downgrade as the agency warned that there was great uncertainty as to the result of talks between the country and its creditors.
Leftist Prime Minister Alexis Tsipras was elected barely two weeks ago on a pledge to renegotiate the terms of a €240bn bailout, including a promise to write off a chunk of the country's debt and scrap austerity measures.
He and finance minister Yanis Varoufakis have toured European capitals in recent days in a bid to drum up support for their plans but Athens has appeared increasingly isolated as it tries to strike a new deal with its European partners.
"The key driver for the review for downgrade is the high level of uncertainty over the outcome of the negotiations between Greece and its official creditors," Moody's said in a statement.
"The outcome could potentially have negative implications for Greece's ability to meet its funding and liquidity needs and for the probability of default on marketable securities."
The move comes after Standard & Poor's cut Greece's long-term sovereign credit rating to B- from B earlier on Friday, warning that liquidity restraints on Greek banks would limit the time the new government has to clinch a deal with its creditors.
A Greek government official said on Friday that the country wanted no more bailout money with strings attached from the European Union and International Monetary Fund.