Nigerian President Umaru Yar'Adua has replaced his chief of defence staff and named new heads of the army, navy and air force in his first major military shake-up since taking office more than a year ago.
The reshuffle is the latest sign that Yar'Adua is throwing off the influence of his predecessor Olusegun Obasanjo. It comes two days after he scrapped the office of chief of staff in the presidency, a post held by one of Obasanjo's top allies.
Yar'Adua appointed Air Marshal Paul Dike, previously head of the air force, as his chief of defence staff late on Wednesday.
Major-General Abdulrahman Dambazau, formerly an army commander in the southwestern city of Ibadan, was made head of the army while Rear Admiral Isaiah Iko Ibrahim, previously head of Naval Training Command in the commercial capital Lagos, was appointed head of the navy.
A presidency statement said the outgoing military chiefs were all retiring from service.
"It could be interpreted as the latest indication of rolling back any lingering influence of the former president," Antony Goldman, an analyst at London-based risk consultancy PM consulting, told Reuters.
The reshuffle means the departure of General Andrew Azazi, who as chief of defence staff was the highest-ranking army officer from the Ijaw ethnic group, the majority tribe in the restive oil-producing Niger Delta.
His replacement, Dike, is also from the Niger Delta. But the fact that he is from the air force leaves Dambazau, who is from Yar'Adua's northern Hausa ethnic group, as the most senior ranking army officer.
The Niger Delta, a vast wetlands region which opens out into the Gulf of Guinea, is the heart of Africa's top oil industry.
A campaign of violent sabotage by militant groups who say they are fighting for a fairer share of the region's natural resources has cut oil output from Nigeria by more than a fifth since early 2006.
Yar'Adua has been under intense pressure to quell the violence as any further threat to Nigerian output risks pushing up volatile world oil prices.
He has pledged to address the root causes of the unrest, promising more development for impoverished communities whose land and water have been polluted by oil extraction, but has also promised tough action against armed groups in the creeks.
Yar'Adua took office in May, 2007, replacing southerner and ex-military ruler Obasanjo in the first democratic handover from one civilian president to another since Nigeria's independence from Britain in 1960.