The king's reply was to order a general order of mobilization of the Bulgarian army. At the same time a note was issued to all foreign representatives in which the Government stated explicitly that Bulgaria had no intention of entering the war; that she had called her men to the colors only to maintain an "armed neutrality," as Holland and Switzerland were doing. In spite of these assurances, Greece also began mobilizing. On September 20, 1915, there appeared a significant statement in the German official report of military operations, to the effect that German artillery, stationed on the Danube opposite Semendria, had opened fire on a Serbian position. Never before had there been mention of German guns so far south. Altogether, the situation in the Balkans was now becoming acute. On September 28, 1915, Sir Edward Grey made a statement in the British Parliament which made the world realize that a crisis in the Balkans was imminent. He announced that efforts were still being made to arrange an agreement between Bulgaria and Serbia and Greece regarding Macedonia, "but," he added significantly, "if Bulgaria assumes an aggressive attitude on the side of our enemies, we will support our friends in the Balkans with all our power, in concert with our Allies and without reserve or qualification." This was followed up by another statement on October 1, 1915, to the effect that German and Austrian officers were arriving in the Bulgarian capital, creating a situation of "the utmost gravity." Within forty-eight hours, Russia issued an ultimatum to Bulgaria demanding that the German and Austrian officers in Sofia be removed within twenty-four hours, otherwise Russia would sever all diplomatic relations with King Ferdinand's Government. To this Bulgaria made no immediate reply, with the result that the Russian Minister left Sofia the next day. Premier Radoslavov, however, on the same day, published an official statement that there were no German or Austrian officers in Sofia and that Bulgaria had no intention of breaking her neutrality. Meanwhile came reports through Greece stating that Bulgarian troops were being massed up against the Serbian frontier. As subsequent events soon proved, Bulgaria was determined to hide her real purpose to the last moment; not until she actually made her first attack did she cease denying her hostile intentions. That Bulgaria was acting in cooperation with the Teutonic allies was obvious, for already the Serbians had observed that great forces were being mobilized across the rivers, along her northern and northwestern frontiers, along the banks of the Danube, the Save, and the Drina.