(BBC) – The US Secretary of State Colin Powell has said the killings in Sudan ‘s Darfur region constitute genocide. Speaking before the US Senate Foreign Relations Committee, Mr Powell said the conclusion was based on interviews with refugees who had fled Darfur . He was speaking as the UN Security Council prepared to debate a second resolution that threatens oil sanctions if Sudan does not stop the abuses. His use of the term genocide is likely to influence the diplomatic debate. The draft resolution presented by Washington is due to be discussed later on Thursday. Up to 50,000 people in Darfur may have died and a million have been made homeless during the conflict. Mr. Powell blamed the government of Sudan and pro-government Arab Janjaweed militias for the killings.