Armenians from around the world have been taking part in public memorial services, to commemorate the 1915 massacre of up to 1.5 million of their ancestors at the hands of the Ottoman Turks.

In Armenia’s capital Yerevan, President Serzh Sargsyan laid a lone yellow rose at a wreath representing a giant forget-me-not flower.

“I am grateful to all those who are here to once again confirm your commitment to human values, to say that nothing is forgotten, that after 100 years we remember,” he told an audience of international dignitaries, who gathered in the former Soviet state.

He was followed by Russian President Vladimir Putin and his French counterpart Francois Hollande, as well as dozens of other officials.

From April 1915 most of the Ottoman Empire’s Armenians were displaced, deported or placed in concentration camps, ostensibly for rebelling and siding with the Russians in World War I. Turkey admits that many were mistreated, but says that the exact numbers of those killed have been exaggerated and there was no systematic policy to eliminate the Armenian minority.