Nigeria's President Muhammadu Buhari has backed the head of the African Development Bank (AfDB) Akinwumi Adesina's re-election bid, despite allegations of corruption and abuse of office against him.

Mr Adesina has denied all the allegations and was cleared of wrongdoing by an internal investigation, but US Treasury Secretary Steve Mnuchin has called for independent investigations.

The Nigerian banker, a former agriculture minister, will seek a second term at the bank's annual general meeting in August.

He visited President Buhari in the capital, Abuja, on Tuesday.

Mr Buhari said in a tweet that "Nigeria stands solidly behind Dr Akinwumi Adesina in his re-election".

Nigeria stands solidly behind @akin_adesina in his re-election bid as President of the African Development Bank (AfDB). We will work with all leaders, and stakeholders in AfDB, to ensure that he re-elected, on the strength of his achievements during this first term. pic.twitter.com/OSl6S99DW8

— Muhammadu Buhari (@MBuhari) June 2, 2020