The issue ratings on Azerbaijan's senior unsecured foreign currency bonds have also been affirmed at 'BBB-'. The Country Ceiling has been affirmed at 'BBB-' and the Short-term foreign currency IDR at 'F3'.

Azerbaijan's ratings reflect the sovereign's low debt (14% of GDP in 2015) and large stock of net foreign assets (72% of GDP), accumulated with the help of double-digit current account surpluses and high oil prices since 2006, Fitch said.

"The affirmation reflects our expectation that the authorities are committed to making the adjustments to capital spending and tax revenue that will ensure the preservation of these buffers. The high dependence on oil and gas is a key rating weakness, with hydrocarbons accounting for 95% of goods exports, 50% of budget revenues and 40% of GDP in 2015," the rating agency said.