A demonstrator sets fire to a Turkish flag as he attends a torch-bearing march marking the anniversary of the 1915 mass killings of Armenians in Ottoman Empire, in Yerevan

A demonstrator sets fire to a Turkish flag as he attends a torch-bearing march marking the anniversary of the 1915 mass killings of Armenians in Ottoman Empire, in Yerevan April 23, 2010. REUTERS/Vahan Stepanyan/PanARMENIAN Photo/Handout (ARMENIA – Tags: POLITICS CIVIL UNREST ANNIVERSARY IMAGES OF THE DAY) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS