KIGALI, April 7: With Western leaders conspicuous by their absence, Rwanda marked the 10th anniversary of its genocide on Wednesday as bewildered and angry as ever at the world's failure to stop one of the 20th century's great crimes.

"Women and girls were gangraped, tortured and maimed for life, if not murdered. The victims were forced to kill their kin or dig their own graves before they were buried alive," President Paul Kagame told 28,000 mourners gathered at a stadium in the capital Kigali.

"We will see each other again in heaven," a choir sang at the memorial site where a crowd of barefoot Rwandans in tattered clothes watched from a hilltop as African presidents arrived in gleaming four-wheel-drive vehicles.

In Geneva, UN chief Kofi Annan said the risk of genocide remained frighteningly real in parts of the world, explaining that Rwanda-style ethnic massacres may be in the making in Sudan and international military force could be needed to stop it.

The UN Secretary-General sounded the alarm in a speech on the 10th anniversary of the Rwanda genocide in which 800,000 Tutsis and moderate Hutus were massacred by Hutu extremists.

He left no doubt he feared something similar might be under way in west Sudan, where UN officials say "ethnic cleansing" is carried out by government-backed Arab militias. Khartoum denies it has any role in unlawful killings in the region.

Annan's initiative on Sudan stood in stark contrast to the low-key approach adopted by the international community on Rwanda in the months leading up the genocide, a failure seen by many Rwandans as a disastrous abdication of responsibility. -Reuters