A source close to the Nigerian president has said that the head of the country's anti-corruption agency, Ibrahim Magu, has been suspended.

He is now believed to be under investigation and was invited to face an investigative panel at the presidential villa in the country's capital, Abuja, on Monday.

The anti-corruption agency, the EFCC, issued a statement saying that the chairman freely "honoured" an invitation from a presidential panel reviewing the activities of the anti-graft organisation.

Nigeria’s state security service, known as the DSS, says he has not been arrested.

Mr Magu was appointed head of the EFCC by President Muhammadu Buhari in 2015.

He was seen as a hardliner in President Buhari's war against corruption - a major focus of his presidential campaign.

Some suggest that Mr Magu stepped on too many toes and the current investigation is politically motivated.

For the moment, the government is yet to officially announce developments in his case.