Updated

Nigeria's President Muhammadu Buhari is ordering an investigation of close allies accused of graft, including the head of the commission meant to fight corruption.

An official with knowledge of the investigation says it will focus on Ibrahim Magu, acting head of the Economic and Financial Crimes Commission. Nigeria's Senate refused to confirm Magu's appointment as chairman of the powerful commission, citing corruption allegations by the Department of State Security.

The official, who spoke on condition of anonymity because he is not authorized to speak to reporters, says the investigation also will focus on Babachir David Lawal, the secretary to the federal government who is in Buhari's cabinet.

Both men have declared their innocence.

Presidential spokesman Garba Shehu confirms the investigation but is not giving names.