"Given the announced terms and conditions of the restructuring, and in line with our criteria, we view the transaction as distressed and tantamount to default," the rating agency said in a statement.
Read also: Holders of Eurobonds of Ukraine have deferred payments - Ministry of Finance
Fitch also downgraded the country's long-term foreign currency rating from C to RD, as it views the debt deferral as a completion of a distressed debt-exchange.
Meanwhile, S&P believes that macroeconomic and fiscal stress caused by Russia's invasion of Ukraine could weaken the Ukrainian government's ability to meet its local currency debt obligations as well, and downgraded the country's local currency rating to CCC+/C from B-/B.
Earlier, Fitch also lowered the credit rating of Ukraine's rail operator, Ukrzaliznytsia, from CCC to C, against the background of the downgrade of Ukraine's sovereign rating.
Read also: Credit rating agency Fitch lowers Ukraine's rating to pre-default level