Armenian Genocide
The Triple Entente warned Ottoman Empire
Turkey (then Ottoman Empire)
On 24 May 1915, the Triple Entente (Russian Empire, France & UK) warned the Ottoman Empire that "In view of these new crimes of Turkey against humanity and civilization, the Allied Governments announce publicly to the Sublime Porte that they will hold personally responsible for these crimes all members of the Ottoman Government, as well as those of their agents who are implicated in such massacres".