This was made known by the Central Bank of Nigeria.
Data from Organization of Petroleum Exporting Countries indicates that a basket of 14 crudes stood at $47.48 per barrel last week, up from $45.21 a barrel it opened the month.
CBN report says external sector weakens in the month under review was due to the decline in crude oil prices from an average of $52.90 per barrel in April 2017 to $51.04 per barrel.
Increased shale oil production in the United States and supply by non-members of the OPEC contributes to the fall in crude oil prices.
Analysts say the fall in foreign reserves is due to CBN’s aggressive interventions in the foreign exchange market aimed at boosting naira and stabilizing the exchange rate.