The Fitch ratings agency on Tuesday, March 13, upgraded Greece out of "restricted default" after Athens carried out the biggest debt writedown in history in a bond swap with private creditors, the Associated Press reported.

International debt inspectors, however, warned the country's recovery will be slower and harder than expected.

The new B- rating, which applies to the new bonds issued under Greek law, is still junk status, meaning they are not investment grade despite the huge cut to Greece's debt pile.

Along with the upgrade, which had been widely expected after Monday's bond swap, Fitch assigned a "stable outlook."

It kept a C rating on foreign-law bonds as the settlement date for their swap is not until April 11. In last week's agreement, 83.5 percent of private investors holding Greek debt agreed to the deal, which will see them face real losses of more than 70 percent on their holdings.

The bond swap was essential for Greece to win approval for a second massive bailout from other eurozone countries and the International Monetary Fund. The country has been surviving since May 2010 on an initial euro110 billion ($144 billion) package of rescue loans.

Over the next few years, Greece stands to receive a total of euro172.7 billion in bailout funds from the eurozone and the IMF, including amounts still left over from the initial bailout, and euro130 billion of new money, Finance Minister Evangelos Venizelos said in a statement.

However, despite the bond swap debt relief, Greece's outlook is grim and the government is expected to have a tough time returning the economy to growth.

The latest assessment by the so-called troika - the European Union's executive commission, the European Central Bank and the IMF - indicated that Greece will have to make strenuous efforts in economic reforms and budget cleanup if its assistance program is to succeed.

A copy of the report, obtained by the Associated Press on Tuesday, says that Greece's economy, now in its fifth year of recession, will recover more slowly than expected and will stagnate in 2013, which growth expected to return only in 2014.

"Implementation risks remain will remain very high," the report says, warning that further bailout money could be needed if Greece remains unable to borrow when the assistance program ends in 2014.