|Goodluck Jonathan, pictured, gave no details on why the officials were replaced [AFP]
Nigeria's president has replaced the heads of the military and security services ahead of January's presidential elections.
Goodluck 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 the head of the State Security Service.
"Mr President thanked them for their dedication to the service of the nation and wished them well in their future endeavours," Ima Niboro, a government spokesman, told reporters on Wednesday in the presidential villa in Abuja.
Niboro 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.
The move comes one day after the country set January 22 as the date for its presidential election.
The announcement also came one day after suspected members of an Islamist sect that launched an uprising last year freed hundreds of inmates in an attack on a prison in northern Nigeria, sparking a fierce gun battle with authorities.
However, there was no indication the moves were in response to the attack.
The president has not yet announced whether he will run in the election, but he is widely expected to do so despite deep disagreement within his ruling Peoples Democratic Party (PDP) over whether he should be its candidate.
Some in the party say the PDP should abandon Jonathan, a southern Christian, in favour of a candidate from the country's mainly Muslim north.
Two northern candidates, including a former military ruler, are seeking the ruling party's nomination.
One political insider who declined to be named told the AFP news agency that the moves signalled a "need to have effective control of the armed forces before elections."
"The context is very much influenced by political tectonics and the commander-in-chief is trying to respond to that," he said.
The statement from the presidency said the military appointments would take immediate effect, but also said they were subject to confirmation by parliament.
The four replaced military chiefs had been appointed by the late president Umaru Yar'Adua in August 2008.
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.