His death was announced on Wednesday morning in a tweet by the head of Nigeria’s state oil company (NNPC).

The circumstances of the death remain unclear.

The Organization of the Petroleum Exporting Countries termed his death "a profound loss to the entire Opec Family, the oil industry and the international community".

Mr Barkindo's six-year tenure was due to end this month and he was visiting his home country as part of farewell activities.

He was instrumental in signing a deal between Opec and non-Opec member countries, including Russia, on stabilising oil output in the global market in 2016.

He was also spearheading the organisation’s drive towards recovery following the unprecedented shocks in the global oil market caused by the Covid-19 pandemic.

He had met President Muhammadu Buhari earlier on Tuesday afternoon at the presidential palace where the president described him as a "worthy ambassador" of Nigeria.

Mr Buhari had also ordered a "befitting reception" event to honour him.