The board of the African Development Bank (AfDB) says it has not asked the president of Africa’s largest multilateral lender, Akinwumi Adesina, to step down.
It said it was treating allegations levelled against Mr Adesina with the seriousness they deserved.
The US had rejected the findings of a probe made into allegations of nepotism - the bank’s ethics committee had exonerated Mr Adesina.
Niale Kaba, the bank's board chairperson, said there was no governance or constitutional crisis at the AfDB.
Mr Adesina is accused by a group of whistle-blowers of appointing relatives to strategic positions at the bank as well as giving contracts to acquaintances. He denies any wrongdoing.
The US holds a 6.5% stake in the bank, the second-largest shareholding after Nigeria.
Denmark, Norway, Sweden and Finland - who are also shareholders - have also written to the Abidjan-based lender backing calls for an independent probe.