article: He was addressing thousands of people in the capital, Kigali, as Rwanda began a week of official mourning to mark the 20th anniversary of the genocide. Many people were overcome by emotion during the ceremony, with some suffering fits. At least 800,000 people - mostly ethnic Tutsis and moderate Hutus - died at the hands of Hutu extremists. The killings ended ended in July 1994 when the Rwandan Patriotic Front (RPF), a Tutsi-led rebel movement, marched into Kigali and seized control of the country. Rwanda's President Paul Kagame and Mr Ban lit a torch which will burn for 100 days - the length of time the genocide lasted. A diplomatic row has prompted Rwanda to bar France's ambassador, Michel Flesch, from attending the event, AFP news agency reports. By Charlotte AttwoodBBC Africa, Kigali It began with just one, and then scores of chilling screams echoed around the stadium. It may be 20 years down the line, but for many here, the wounds are still too fresh to bear. Paramedics went up and down the terraces, comforting and removing those who could not cope with the memories. I saw one man being carried out during the dramatisation of the recent history of Rwanda. The play itself was a very clear depiction of the government's interpretation of what caused the tragic episode in the country's history. Half-way through, a jeep drove in carrying the "colonialists" who marched onto the stage. They swapped their colonial straw hats for the blue helmets of the UN and then deserted the people, leaving a bloodbath in their wake. Soldiers - representing the governing RPF - troop in to rescue a devastated population. The week of mourning began with a wreath-laying ceremony at the national genocide memorial, followed by the lighting of a flame at the Amahoro Stadium in Kigali, where UN peacekeepers protected thousands of people during the genocide. The torch has been carried across the country for the past three months, visiting 30 districts and passing from village to village. Thousands of people packed the stadium, having queued for hours through the fog, reports the BBC's Charlotte Attwood from the scene. Many of them reacted with uncontrollable emotion to the stories, speeches and performances recalling the genocide, our correspondent says. Some of them had to be led out of the stadium while others had fits, she adds. Traditional mourning songs were broadcast over the sound systems. There was also a dramatisation of Rwanda's recent history, which our correspondent says was a clear depiction of the government's interpretation of events. In the play, a jeep carrying "colonialists" arrives, who swap their straw hats for UN blue helmets. They then desert the people, who are saved by the governing RPF. UN personnel in Rwanda during the genocide showed "remarkable bravery", Mr Ban told the crowd, according to AP. "But we could have done much more. We should have done much more," he said. "In Rwanda, troops were withdrawn when they were most needed," he added. "One year later in Srebrenica, areas proclaimed 'safe' by the United Nations were filled
summary: The UN is still ashamed over its failure to prevent the 1994 genocide in Rwanda, UN chief Ban Ki-moon has said.