Nigeria first lady: President 'recuperating fast' in London

Nigeria's first lady says the president's health is improving after he has spent nearly one month in a London hospital for an unspecified illness.

President Muhammadu Buhari's ill health has prompted fears as this is the second time this year he has been abroad for extended medical treatment.

A spokesman for first lady Aisha Buhari says she has returned to Nigeria after visiting her husband in London. Upon her return she conveyed that the president "is recuperating fast."

The exact nature of Buhari's illness is unknown although he has spoken of receiving blood transfusions.

Observers fear political unrest could erupt in Nigeria, particularly in the predominantly Muslim north, should Buhari not finish his term in office. The previous president was a Christian from the south.