Let the main players speak from their own words:
*Mehmed Talat Pasha, the Ottoman Interior Minister:
"Kill every Armenian man, woman, and child without concern."
*Dr. Max Erwin von Scheubner-Richter, the ambassador of one of the Central Powers, allied with the Ottoman Empire:
"The partisans of Ittihad are unabashedly conceding that their ultimate aim [Endziel] is the total annihilation (ganzliche Ausrottung) of the Armenians of Turkey, adding, "After the war we no longer will have any Armenians in Turkey.""
*Enver Pacha, one of the effective rulers, to the crowd:
"The Ottoman Empire should be cleaned up of the Armenians and the Lebanese. We have destroyed the former by the sword, we shall destroy the latter through starvation."
To the U.S. Ambassador Morgenthau (incidentally more known in Germany than in the U.S.):
"You are greatly mistaken. We have this country absolutely under our control. I have no desire to shift the blame onto our underlings and I am entirely willing to accept the responsibility myself for everything that has taken place."
You can find here other quotes from important contemporaries about how the Young Turks were slaughtering Armenians and were proudly saying this to foreign statesmen.
Moreover, Dr. Bernard Lewis said, in the begining of his career, Armenians were exterminated by the Young Turks and then changed his mind, with some making the hypothesis he wanted to preserve the links between Israel and Turkey.