 The 5th Army with eight divisions was based in Tripolitania, the western half of Libya opposite Tunisia and the 10th Army with six infantry divisions, held Cyrenaica in the east.When war was declared, the 10th Army moved the 1st Libyan Division "Sibelle" to the frontier from Giarabub to Sidi Omar and XXI Corps from Sidi Omar to the coast, Bardia and Tobruk.The XXII Corps moved south-west of Tobruk to act as a counter-attack force.