Nigerian President Umaru Musa Yar'Adua has ordered the retirement of 40 of the military's most senior commanders.

They include the generals in charge of the army's five divisions.

Nigeria has been ruled by the military for 30 of the 47 years since independence but a coup is no longer likely, a BBC correspondent says.

Mr Yar'Adua was sworn in May - the first time one elected leader had handed power to another, although but the elections were widely condemned.

Former President Olusegun Obasanjo ordered a similar purge of the military shortly after his inauguration in 1999.