Nigeria’s central bank governor Lamido Sanusi has been suspended after he alleged that $20bn (£12bn) in oil revenue had gone missing.
President Goodluck Jonathan said there had been “far-reaching irregularities” under Mr Sanusi’s watch.
BBC Abuja editor Bashir Saad Abdullahi says the allegation of missing oil revenue has come as a huge embarrassment for the government.
Nigeria’s state oil firm has denied failing to account for the money.
The Nigerian National Petroleum Corporation said the allegations were “unsubstantiated” and showed “little understanding of the technicalities of the oil industry”.
Mr Sanusi is currently in Niger attending a meeting of regional central bank heads.
President Jonathan asked him to resign in December but Mr Sanusi refused, sources told the BBC Hausa service.
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