On August 19, 1915, a German submarine torpedoed without warning the British White Star Line passenger liner, Arabic, with the loss of two United States citizens. This attack occurred soon after the exchanges of notes that followed the torpedoing similarly of the RMS Lusitania in which the United States had insisted that the lives of non-combatants could not lawfully be put in jeopardy by the capture or destruction of unresisting merchants. The German act indicated that it was still uncertain whether Germany had accepted the American position. After seeking to justify the attack on the ground that the Arabic was attempting to ram the submarine, the German government disavowed the act and offered indemnity. Claims of United States citizens arising out of this and similar cases were eventually adjudicated under the Treaty of Berlin (1921) by the Mixed Claims Commission, United States and Germany, following World War I.