On 24 July 1914, the Hungarian Premier, Istvan Count Tisza (pictured), sent a strictly private telegram to the Austro-Hungarian Minister of Foreign Affairs, Leopold Count Berchtold. In the telegram, Tisza states that he is in favour of an Austro-Hungarian mobilisation.
Count Tisza to Count Berchtold. Budapest, 24 July 1914.
Cyphered.— Strictly private.
I beg Your Excellency to insist in my name, that in case Servia gives an unsatisfactory answer [to the ultimatum] the mobilisation would undoubtedly become necessary. The slightest hesitation would be followed by fatal consequences.
Source: 1919 Austro-Hungarian Red Book, with minor edits.