Armenia marked the centenary on Friday of a mass killing of Armenians by Ottoman Turks with a simple flower-laying ceremony attended by foreign leaders as Germany became the latest country to respond to its calls for recognition that it was genocide.

Turkey denies the killing of up to 1.5 million Armenians in what is now Turkey in 1915, at the height of World War I, constitutes genocide and relations with Armenia are still blighted by the dispute.

Parliament in Germany, Turkey's biggest trade partner in the European Union, risked a diplomatic rupture with Ankara and upsetting its own many ethnic Turkish residents by joining the many Western scholars and two dozen countries to use the word.