Nigeria's Minister of Innovation, Science and Technology Uche Nnaji has resigned just days after allegations emerged that he had forged his academic credentials.

The resignation follows a newspaper investigation that claimed Nnaji submitted falsified certificates to President Bola Tinubu during his ministerial appointment in 2023.

Presidential spokesperson Bayo Onanuga confirmed Nnaji's resignation in a post on X late on Tuesday, quoting the minister as saying he had been "a target of blackmail by political opponents".

Nnaji has denied the accusations of forgery and and has insisted that he did graduate from the University of Nigeria, Nsukka (UNN) with a degree in Microbiology/Biochemistry.

The forgery allegations have sparked outrage among some Nigerians, following a two-year investigation by the Premium Times newspaper.

Last week, UNN reportedly told the publication that it had no records confirming that the minister had graduated with a Bachelor of Science degree in 1985, as he had claimed.

A senior university official told the paper that Nnaji was admitted in 1981 but never completed his studies or received a certificate.

The National Youth Service Corps (NYSC) also said the mandatory certificate of national service Nnaji presented in April 2023 could not be verified.

Opposition leader Atiku Abubakar has called for an independent and transparent investigation into the matter, saying Nnaji should have been "summarily dismissed and prosecuted for deceit and falsification".

"Nigerians deserve to know the truth about those who preside over their lives and resources," Abubakar posted on X.

The suspension or removal of a minister is rare in Nigeria - Nnaji is only the second to leave office since President Tinubu assumed power in May 2023.

Last January, the then Humanitarian Affairs and Poverty Alleviation Minister Betta Edu was suspended following public outrage over a corruption scandal. At the time Dr Edu, 37, denied any wrongdoing.

Tinubu's predecessor, the late Muhammadu Buhari, sacked only two ministers during his eight-year tenure.