Abuja - Nigerian President Goodluck Jonathan replaced the heads of the military and security services on Wednesday, consolidating his hold on power months before elections in Africa's most populous country.

Jonathan promoted former air force chief Air Marshal Oluseyi Peterin to Chief of Defence Staff and named new heads of the air force, army and navy. He also removed the Inspector General of Police and head of the State Security Service.

He said the tenures of the outgoing service chiefs had expired at the end of August and that the new appointments would take immediate effect, but gave no further details.

Jonathan has not yet said whether he will stand in the January polls but recent announcements, including a major blueprint to end chronic power shortages, have looked more like campaign promises and most Nigerians expect he will.

Nigeria emerged from decades of coups and military rule 11 years ago but the military remains a potent background force, with retired generals reinventing themselves as politicians and businessmen, and still pulling the strings of power.

The last military shake-up in Nigeria was just over two years ago, when then President Umaru Yar'Adua named new service chiefs in a bid to assert his authority and shake off the influence of his predecessor Olusegun Obasanjo.

Similarly, the latest reshuffle suggests Jonathan is asserting his authority four months after Yar'Adua died in office, and ensuring he is in control of the military in the run-up to the presidential, parliamentary and state polls.