This is contained in a statement signed by Mr Paul Nwabuikwu, spokesman to the Minister of finance, Dr Ngozi Okonjo-Iweala, in Abuja.
The downgrading was attributed to the decline in oil price in last seven months which affected external position and external vulnerability of the country.
“Nigeria is one of many oil producing countries downgraded by S&P due to the impact of the steep drop in global oil prices on their economies,” it said.
It further noted that it based its decision on significant political risk arising from the coming elections as well as the impact of insurgency in the North East.
The Agency put annual real GDP growth of the country at five per cent, in spite the troubles in the northeast and the fall in oil prices.
“This is slightly higher than the 4.8 per cent projected by the IMF and is quite robust by current global standards,” it said.
According to the statement, the GDP growth is being driven by the non-oil sectors of the economy.
Other countries downgraded by the agency are Russia, Bahrain, Congo (Brazzaville), Kazakhstan, Oman, Venezuela, Angola and Gabon.
It also assigned a negative outlook to Azerbaijan and Saudi Arabia.(NAN)