New York - A strategic review of the UN peacekeeping mission in Democratic Republic of Congo says holding a long delayed presidential election that is credible will be key to ending the political crisis that is the main driver of the country's increasing violence and human rights abuses.Secretary-General Antonio Guterres warned in the report to the UN Security Council that Congo risks "sliding back into conflict," but he said President Joseph Kabila also has a "historic opportunity to cement his legacy" as the first DRC president to hand power to an elected successor.In the 27-page report, obtained Monday by The Associated Press, Guterres said that "all efforts" must be geared to keeping alive a December 31 agreement calling for elections by the end of 2017 and to "ensuring the protection of civilians and human rights".But the UN chief said that without tangible progress on completing voter registration, early publication of "a credible electoral calendar" and the implementation of confidence-building measures called for in the election agreement, DRC "is likely to enter a period of extreme volatility." This will be marked "by increasingly open confrontation between the opposition and the government and greater unrest among a population facing untold hardship," he said.'Undeniable tenacity'The vast Central African nation has seen widespread anger and unrest over Kabila's stay in power after his mandate ended in December 2016. He is barred from running under the December31 agreement, but his government has delayed voting, saying preparations are not complete.Kabila told the UN General Assembly's annual ministerial meeting two weeks ago that the election timeline should be released "soon" and that his country is moving toward a vote with "undeniable tenacity". He said 42 million of the projected 45 million people eligible to vote have already registered, and the process recently began in the last area to open registration, the violence-wracked Kasai region.Guterres said the UN remains committed to supporting implementation of the December 31 agreement and he urged stepped up efforts from DRCs neighbours, regional groups and the African Union to create conditions for credible elections.The secretary-general said he is equally committed to ensuring that the UN peacekeeping mission, known as Monusco, "is able to protect civilians in a context of spreading local conflict and increasing human rights abuses by the national security forces and armed groups." According to the UN, 57% of human rights violations documented in Congo since the beginning of 2017 "can be attributed to state agents," he said.The review recommends that Monusco shift "towards a more agile and flexible mission" and protects protecting civilians "through early warning, prevention and, where required, the projection of military force".Guterres said the force will also focus on its other main priority, supporting implementation of the December 31 agreement. He said the force has played a critical role, with the UN. Development Program, in supporting voter registration, where women who have been historically excluded from the political process make up 48% of those registered.If credible elections lead to a peaceful transfer of power, Guterres said, Monusco would focus primarily on supporting a peaceful transition at all levels of government while continuing to protect civilians. He said the force's strength also would be reduced.Monusco is the biggest and costliest of the 16 far-flung UN peacekeeping missions. It has a budget of $1.14 billion and about 21 600 people, including over 16 500 soldiers and over 1 350 police.The secretary-general stressed that much depends on a fair presidential election. "The national political crisis triggered by the failure to hold elections on time can have consequences for the country and the surrounding region," he warned.The political crisis has also aggravated the humanitarian situation and compounded an economic crisis "that has fueled popular frustration and raised the specter of widespread social unrest," he said.DRC is facing one of the worst humanitarian crises in Africa, with 7.7 million people in acute need of food as of June 2017, compared to 5.9 million a year earlier, Guterres said. And 82 percent of the population lives below the absolute poverty line of $1.25 a day, which is "one of the highest poverty rates in the world."