President Joe Biden is gearing up to formally recognize the Ottoman Empire’s killing of 1.5 million Armenians in the early 20th century as genocide, according to multiple reports. Biden would become the first sitting U.S. president to label the systematic killings as genocide, and he will likely provoke the ire of Turkey in the process. Officials cited by Reuters said the announcement is expected to happen on Saturday, the 106th anniversary of the World War I-era campaign that historians say saw hundreds of thousands of Armenians deported from modern-day Turkey and forced into an agonizing death march. “My understanding is that he took the decision and will use the word genocide in his statement on Saturday,” a source told Reuters of Biden’s plan to make the announcement. Turkey has long denied that the killings amounted to genocide, and Foreign Minister Mevlut Cavusoglu said earlier this week that any such declaration would “harm ties” between the U.S. and Turkey.