President Buhari's plagiarises parts of a speech by Barack Obama, apologises afterwards

Several passages of a speech Mr Buhari made on 8 September overlapped with President Obama's address after winning election in 2008.

His office admitted the sentences were "too close to be passed as coincidence".

The two men are due to meet at the UN General Assembly next week.

"There was a mistake by an overzealous staff and we regret that this has happened," Mr Buhari's spokesman Garba Shehu wrote on Twitter, saying those responsible would be punished.

"President Buhari urges Nigerians to look beyond this incident and focus on the message of change which the country needs in order to restore our cherished value systems."