ABUJA (Reuters) - Nigerian President Muhammadu Buhari sacked the head of an amnesty programme for former militants in the country’s oil and gas-producing heartland, amid allegations of graft.

Funding of the former Niger Delta militants under the 2009 amnesty has been key to maintaining relative stability in the southern region and preventing attacks on energy facilities in Africa’s biggest oil producer. Crude oil sales make up two-thirds of government revenue.

But attacks resumed in 2016, contributing to pushing Africa’s biggest economy into recession that year as oil production was cut from a peak of 2.2 million barrels per day (mbpd) to near 1 mbpd, Nigeria’s lowest level for at least 30 years.

Announcing the dismissal of Paul Boroh, a retired senior army officer, Buhari ordered the country’s national security adviser to investigate the programme’s activities since 2015, “especially allegations of financial impropriety”.

The announcement came in an emailed statement from the president’s spokesman, which gave no details of the allegations.

The programme entitles each former militant to a monthly stipend and job training.

Boroh is being replaced by Charles Quaker Dokubo, currently Director of Research and Studies at the Nigerian Institute of International Affairs, a think tank.