Nigerian President Muhammad Buhari is traveling to London to attend an education summit and will use the trip to go for a health check-up, the presidency has announced.

Mr Buhari will participate in the Global Education Summit co-hosted by UK Prime Minister Boris Johnson and President of Kenya Uhuru Kenyatta, a statement said.

He will also spend days undertaking "an earlier scheduled medical check-up".

Mr Buhari will return to Nigeria by the second week of August, said Femi Adesina, the president's media aide.

The 78-year-old leader has made several trips to the UK for medical reasons since taking office in 2015.

During one such trip in 2017 he spent several months in London. The nature of his illness has never been disclosed by officials.

His last visit was at the end of March when he spent about two weeks.

His frequent medical trips have been widely criticised, especially given the poor state of Nigeria's public healthcare system.