Abuja - Nigeria's state oil firm has appointed four new group executive directors and reduced its management staff from 122 to 83, it said on Tuesday.
Last week former Exxon Mobil executive Emmanuel Ibe Kachikwu was appointed as the new head of Nigerian National Petroleum Corporation (NNPC) and he dismissed all of the company's executive directors the next day after a government directive.
President Muhammadu Buhari has made a number of changes at NNPC as part of a crackdown on corruption and mismanagement in Nigeria's main money earner.
The appointments, approved by Buhari, include Maikanti Baru as group executive director for exploration and production and Isiaka Abdulrazaq as group executive director for finance and services.
Also read: New head of NNPC sacks top management
The other appointments were Dennis Nnamdi Ajulu, as group executive director for refining and technology, and Babatunde Victor Adeniran, who is now group executive director for commercial and investment.
"The new appointments are in line with the federal government's aspiration to transform the corporation into a lean, efficient, business-focused, transparent and accountable national oil company," said the emailed statement.
The statement added that more than 30 members of top management staff had been retired, "reducing the number from 122 to 83".
Buhari has said about 250,000 barrels of oil were being stolen each day and that his government was aiming to recover an estimated $150 billion in stolen funds with U.S. assistance.
In 2013, the then central bank governor Lamido Sanusi said tens of billions of dollars in oil revenue had failed to make it into state coffers, which the company denied.
In June, Nigeria's National Economic Council said NNPC had earned 8.1 trillion naira ($41 billion) from 2012 until the end of May, but only paid 4.3 trillion to the federal government.