Nigeria's president has fired the head of the country's main anti-corruption agency.

Ibrahim Lamorde is the latest in a string of senior officials to be sacked by Muhammadu Buhari, who took office in May promising to halt the graft that keeps the oil-rich West African nation impoverished.

Lamorde was a police commissioner when he became chairman of the Economic and Financial Crimes Commission four years ago. The commission itself has been accused of corruption and of politically targeting opponents of the incumbent president.

A statement from the presidency on Monday night said Lamorde is taking "terminal leave."

Buhari has appointed Assistant Police Commissioner Ibrahim Mustafa Magu as the agency's acting commissioner.

Lamorde's commission investigated more people since Buhari's inauguration than in all his three previous years in office.