The operation was to be directed and observed by Mussolini, who arrived in Tirana on 2 March 1941; Italian radio announced that Mussolini would lead the Italian attack. The offensive began on 9 March, under General Carlo Geloso and started with heavy bombardment of Greek positions by artillery and aircraft. Eleven infantry divisions attacked with the support of the 131st Armoured Division Centauro. a heavy artillery barrage and air bombardment; on the main sector, held by the Greek 1st Division, over 100,000 shells were dropped on a front. Despite repeated assaults and heavy shelling, the positions of 1st Division held during 9-10 March. The attack was mainly directed against the 1st, 2nd, 5th, 11th, 15th and 17th divisions of the Greek army and was followed by repeated infantry assaults between the rivers Osum and Vjosë, an area dominated by Mount Trebeshinë.