Rwanda's president said the international community "failed all of us", as he marked 30 years since the 1994 genocide that killed around 800,000 people.
President Paul Kagame addressed dignitaries and world leaders who had gathered in Rwanda's capital, Kigali, to commemorate the bloodshed.
"Rwanda was completely humbled by the magnitude of our loss," he said.
"And the lessons we learned are engraved in blood."
On this day in 1994, extremists from the Hutu ethnic group launched a 100-day killing spree, in which members of the Tutsi minority and Hutu moderates were slaughtered.