Iranian air defence forces will conduct five days of aerial manoeuvres from Sunday to thwart the aerial threat posed by an imaginary enemy on Iran's nuclear facilities .The army air defence chief Brigadier General Ahmad Mighani said that it is the duty of defence forces to protect nation's vital facilities .<br/>Iran's still un-operational nuclear plant is in the southern Bushehr province and its other nuclear sites, namely uranium enrichment plants, are in Isfahan and near Tehran.<br/>