The president of Nigeria Muhammed Buhari has announced leaving the post of petroleum minister after recently declaring to keep the post for himself vowing to fight corruption surrounding the oil industry.

“He can’t be president and oil minister at the same time,” Femi Adesina, Buhari’s spokesman told Bloomberg. “He will supervise the ministry, so there will be no petroleum minister. Maybe he will appoint a minister of state, which is a junior minister.”

Buhari last week, sent a list containing names of 21 candidates including four ex-governors, Emmanuel Kachikwu the Newly appointed Group Managing Director of the Nigerian National Petroleum Corporation (NNPC), and Kemi Adeosun to the senate without attaching their portfolio. The senate however is to start evaluating the list.

According to Adeshina, the constitution warrants that the president chooses a minister from each of the 36 states in Nigeria. He is however not to present more nominees to the senate until after the first list has been examined.

Muhammed Buhari had served as oil minister in the 1970s and also as the head of the Petroleum Trust Fund in the 1990s.