Nigeria’s President Muhammadu Buhari has had to put off a medical trip to London planned to begin on Friday, his office has said.
On Thursday, a statement from one of his aides said he was leaving for the UK capital “for a scheduled medical follow-up".
It would have been the 78-year-old’s second trip to see doctors in London this year.
He has made several visits to the UK for medical reasons throughout his presidency, which began in 2015, but the nature of his illness has never been disclosed.
No reason has been given for the postponement of this trip, but Friday’s statement said a new date would be announced.
Mr Buhari has been criticised in the past for travelling abroad for treatment, especially as the country's public health service remains severely underfunded.