 Complete the following phrase:  In 1914, the Ottoman Empire joined the Central Powers, formally entering into World War I with a surprise attack on Russian positions in the Black Sea. During its invasion into Russian and Iranian territories, the Ottomans carried out massacres on the local Armenian populations, escalating the violence into a genocide that ultimately resulted in the deaths of an estimated 1 million Armenians. Many of the leading figures in the Armenian Revolutionary Federation were among those that were 