Armenian President Serzh Sargsyan declared that “nothing is forgotten” at a ceremony to mark the centenary of the slaughter of as many as 1.5 million Armenians in the Ottoman Empire, while Germany defied Turkey’s objections to join other states for the first time in describing the killings as genocide.

Russian President Vladimir Putin and French President Francois Hollande were the most prominent world leaders to attend Friday’s commemoration at the genocide memorial in the Armenian capital, Yerevan. Turkish European Union Affairs Minister, Volkan Bozkir, became the first government representative to attend a mass at the Armenian church in Istanbul for the victims of the 1915 killings. Turkey denies there was a genocide, while acknowledging atrocities occurred.

“Even 100 years later, we remember and demand,” Sargsyan said in a speech challenging Turkish denials after he and representatives of 60 countries placed yellow roses in the center of a large forget-me-not wreath to mark the centenary. Russia mourns “one of the most terrible tragedies in the history of mankind” together with Armenians, Putin told the gathering.

The centenary of the World War I killings is being marked amid unprecedented international recognition that what took place was genocide. Pope Francis and the European Parliament called last week on Turkey to recognize the genocide, while the visit to Armenia this month of U.S reality-TV star Kim Kardashian and her rapper husband Kanye West brought global media attention to the issue.

Genocide Vote

German Chancellor Angela Merkel’s ruling coalition presented a parliamentary resolution on Friday that called the killings a genocide. “We have to understand that the denial of this genocide has a special role for Turkey’s national identity,” Norbert Roettgen, who heads the lower house’s foreign affairs committee, said in a speech to parliament. “We can’t condone that with silence. Even 100 years later isn’t too late. This is overdue.”

Germany, Turkey’s largest trading partner in the European Union, introduced the measure a day after President Joachim Gauck called the killings an example of “the genocides that left such a terrible mark on the 20th century.” The parliament in Austria, Ottoman Turkey’s ally with Germany in World War I, labeled the massacres as genocide on Tuesday, prompting Turkey to recall its ambassador.

Gallipoli Campaign

U.S. President Barack Obama, who was represented in Yerevan by Treasury Secretary Jack Lew, issued a statement that didn’t characterize the “mass atrocity” as genocide to avoid offending Turkey, while calling for “a full, frank, and just acknowledgement of the facts.” Obama made a pre-election pledge in 2008 that “as President I will recognize the Armenian Genocide,” though he has avoided doing so.

Turkey is “respectful of the pain experienced by our Armenian brothers,” Bozkir told journalists in Istanbul. “We are not opposed to commemoration of these painful events as witnesses.”

Turkey hosts events Friday to mark the 1915 Gallipoli campaign after President Recep Tayyip Erdogan changed the date of the ceremony, which members of the British royal family and Australian Prime Minister Tony Abbott will attend, to clash with the one in Yerevan. Turkey “can never accept such a sin, such guilt,” Erdogan said last week in reference to the genocide.

The dispute is at the core of tensions between Armenia and Turkey, who have no diplomatic ties and face each other across a closed border. Turkey rejects the death toll and argues that the killings that took place were the consequence of war after some Armenians joined Russian troops fighting the Ottomans.