Kigali, Rwanda ? Survivors of the 1994 genocide in Rwanda on Wednesday buried the remains of hundreds of victims recovered from pit-latrines and mass graves to mark the 10th anniversary of the government-orchestrated slaughter that left more than 500,000 people dead.

The symbolic burial on a hillside marked the beginning of a week of mourning for the Tutsis and political moderates from the Hutu majority who were killed during the 100-day slaughter that tore apart this small central African nation.

The remains of hundreds, locked in 19 communal coffins, will be lowered into tombs by families and genocide survivors keen to give loved ones a ritual burial years after they were killed by their neighbors under the orders of the extremist Hutu government then in power.

President Paul Kagame — whose then-rebel force ended the genocide by ousting the extremist government — laid a wreath on a 20th coffin before it is lowered into the grave. He then lit a flame that will burn for 100 days at the central courtyard of the Kigali national memorial center.

“Traditionally in Rwanda there is a fire that’s lit during seven days of mourning,” said James Smith of Aegis Trust, a British group that designed and helped construct the $2 million memorial site being inaugurated Wednesday. The memorial flame will burn for 100 days to mark the span of the genocide.

“The flame reflects the traditional Rwandan culture of lighting fire during a period of mourning,” Smith told The Associated Press.

As the remains were buried, thousands gathered at the Amahoro Stadium for a day of reflection on the horrors and pain of the genocide.

Cynthia and Sonia Dushime, 11-year-old twins whose entire family was killed during the genocide, will hand a torch to Kagame for the lighting ceremony.

“Today is a special day because we get to remember our dead in a special way and bury them,” Cynthia said. “We miss our mama and papa, we never got to know them.”

Apollan Odetta, a survivor of the 1994 Rwandan genocide, lights candles at a mass grave in Nyamata, Rwanda. Rwanda today is observing the 10th anniversary of the genocide that began April 7, 1994. Some 500,000 people died in the 100-day killing spree.

Sonia added: “But we are told that our mom was very kind.” Her voice then trailed off as she stared at the ground.

At noon, Rwanda, a former Belgian colony with 8.2 million people, will fall silent for three minutes before survivors describe their experiences to the nation.

Leaders from South Africa, Kenya, Ethiopia, Burundi, Belgium, Tanzania and Congo flew to Rwanda for the commemoration, as well as European and U.S. officials.

Later Wednesday, Belgian Prime Minister Guy Verhofstadt is expected to inaugurate the memorial for 10 Belgian peacekeepers who were killed on April 7, 1994, while they tried to protect moderate Prime Minister Agathe Uwilingiyamana.

The genocide began hours after the mysterious downing of the plane carrying President Juvenal Habyarimana on April 6, 1994. But Tutsis, who now dominate the central African nation’s government and army, say the slaughter began April 7 in part because they don’t want the date to coincide with the shooting down of Habyarimana’s plane — a date with political meaning for radical Hutus.

Commemorations will be capped by an evening of mourning during which visiting heads of state and officials will join Rwandans at the Amahoro Stadium for 100 minutes of poems and choreographed movements by 800 children and the youth.

The killing was orchestrated by the Hutu-extremist government then in power. Government troops, Hutu militia and ordinary villagers spurred on by hate messages broadcast via radio went from village to village, butchering men, women and children. Most of the victims where members of the Tutsi minority and politically moderate Hutus.

The genocide drew unusual apologies from then-President Clinton and the United Nations for failing to intervene. Romeo Dallaire, the Canadian general whose U.N. peacekeepers had to stand by helplessly as the slaughter unfolded, went into a suicidal depression. The violence spilled into neighboring Congo where it stoked two civil wars.