Passage: The scale of the crisis led to warnings of an imminent disaster, with United Nations Secretary-General Kofi Annan warning about the risk of genocide. The scale of the Janjaweed campaign led to comparisons with the Rwandan Genocide, a parallel denied by the Sudanese government. Independent observers noted that the tactics, which included dismemberment and killing of noncombatants, including young children and infants, were more akin to the ethnic cleansing used in the Yugoslav wars and warned that the region's remoteness meant that hundreds of thousands of people were effectively cut off from aid. The Brussels-based International Crisis Group had reported in May 2004 that over 350,000 people could potentially die as a result of starvation and disease.

Question: What method of mass killing has the scale of the Janjaweed often been referred to as?
Rwandan Genocide