The Greek artillery began firing a preparatory bombardment on March 4, continuing through the day. It is estimated that the Greeks fired 150 rounds per gun in this bombardment, while Ottoman counter-fire was hampered by lack of ammunition.[19] The assault was launched on 5 March [O.S. 20 February] 1913, with three Greek infantry divisions—the 4th, 6th and 8th Infantry Divisions—thrusting against the eastern and western sectors of the defensive perimeter.