Nigeria’s central bank on Friday ordered banks and financial institutions to close down accounts involved in the transfer or exchange of cryptocurrencies, warning of sanctions it they did not comply. Africa’s largest economy has become a huge market for cryptocurrency trade, but the central bank has warned for several years that the currencies are not regulated or legal tender in Nigeria. Cryptocurrencies are seen by some Nigerians as a safe haven in a petroleum-reliant economy battered by swings in oil prices damaging shutdowns last year to curb the coronavirus pandemic. “The bank hereby wishes to remind regulated financial institutions that dealing with cryptocurrencies or facilitating payments for cryptocurrency exchanges is prohibited,” it said in a statement posted on its website. It said all banks and financial institutions were directed to identify persons and/or entities involved in cryptocurrency exchanges and close their accounts immediately. “Breaches of this directive will attract severe regulatory sanctions,” it said. A spokesman at the bank did not respond to calls seeking more details on the decision.