Rwanda is beginning a week of official mourning to mark the 20th anniversary of the country’s genocide today.
President Paul Kagame is to light a torch which will burn for 100 days – the length of time the genocide lasted.
A diplomatic row has prompted France’s justice minister to pull out of the commemorative events, but Paris says its ambassador will be present.
At least 800,000 people – mostly ethnic Tutsis and moderate Hutus – died at the hands of Hutu extremists in 1994.
Most of the victims of the genocide were attacked with machetes during 100 days of slaughter that began on 6 April 1994, shortly after Hutu President Juvenal Habyarimana was killed when his plane was shot down over the Rwandan capital.
Some Christian leaders were implicated in the violence.
The killings ended in July 1994 when the Rwandan Patriotic Front (RPF), a Tutsi-led rebel movement that entered the country from Uganda, marched on Kigali and seized control of the country.
The week of mourning begins with a wreath-laying ceremony at the national genocide memorial followed by the lighting of a flame at the Amahoro Stadium in the capital, Kigali.
The torch has been carried across the country for the past three months, visiting 30 districts and passing from village to village.
International leaders including former British PM Tony Blair, South African President Thabo Mbeki and UN Secretary General Ban Ki-moon are due to attend the ceremony.