KYIV, Nov 25 – Moody's Investors Service changed the outlook on the Government of Ukraine's ratings to positive from stable. At the same time, Ukraine's long-term issuer and senior unsecured ratings have been affirmed at Caa1.

"The affirmation of Ukraine's Caa1 ratings reflects its – while showing signs of improvement – significant external vulnerability," Moody's said.

The sizeable external debt repayments due over the coming years would – in the absence of a new International Monetary Fund (IMF) program – require continued market access. At the same time, the risk of a new flare-up in geopolitical tensions continues to constrain upward movement in the credit rating at this time.