U.N. Secretary-General Ban Ki-moon said Wednesday the future of Sudan hinges on two upcoming referenda which could split Africa's biggest country in two. There are less than 100 days before the referenda scheduled for January 9 next year, with South Sudan voting on whether to form a new country and voters in the oil-rich central region of Abeyi voting whether to remain in Sudan or become part of a possible new country in the south. "The stakes could not be higher," Ban said. "Handled properly, the January ballot could help build a future that improves the lives of all Sudanese. Handled poorly, it could spark conflict, with consequences across Africa and beyond." The United Nations is concerned that the referenda may not be held on time and that South Sudan could unilaterally declare independence, a move which could spark another civil war. The referenda are key provisions of a 2005 peace agreement which ended a civil war that claimed the lives of up to 2.5 million people. Ban said he is particularly concerned about "the lack of progress in forming the Abyei Commission," which is tasked with demarcating Abyei's borders. The U.N. chief recently appointed a panel to oversee the elections. The panel will arrive in Sudan next week, he said. Meanwhile, the U.N. Security Council was scheduled to visit Sudan on Wednesday. The 15-member council left New York City on Monday and visited Uganda on Tuesday before traveling to Sudan. "The principle purpose of the trip is to underscore the council's commitment to holding the referenda on time, and that they be a credible representation of the people of Southern Sudan and Abyei, and that the results be respected," U.S. Ambassador Susan Rice told the Associated Press. Council members are scheduled to fly to Juba, the regional capital of Southern Sudan, and then on to conflict-torn western Darfur before visiting Khartoum.