 It is sometimes incorrectly claimed that Russian counter-battery fire destroyed two German heavy mortars; these guns were withdrawn for operations elsewhere.The Germans launched a full frontal offensive on the fortress at the beginning of July; the attack included 14 battalions of infantry, one battalion of sappers, 24–30 heavy siege guns, and 30 batteries of artillery equipped with poison gases led by Field Marshal Paul von Hindenburg.Russian defenses were manned by 500 soldiers of the 226th Infantry Regiment Zemlyansky, and 400 militia.