The EU said Sunday that "doubts remain" over the result of the Democratic Republic of Congo's disputed election, after the country's highest court declared Felix Tshisekedi president, outraging opponents.With fears running high that the poll dispute could plunge the perennially unstable central African nation into fresh turmoil, an EU spokeswoman pleaded for all sides to refrain from "any action that could lead to violence".DR Congo's constitutional court threw out a legal challenge by runner-up Martin Fayulu early Sunday, paving the way for Tshisekedi to take over from long-ruling strongman Joseph Kabila."We take note of the announcement by the Constitutional Court last night," an EU spokeswoman said."As expressed by the AU (African Union) high level consultative meeting on Thursday in Addis, doubts remain regarding the conformity of the result," she added.The AU's chairman, Rwandan President Paul Kagame, is due in Kinshasa on Monday, and the EU called on all parties to cooperate with his mission.The AU had called for the final results to be delayed. But another regional bloc, the 16-nation Southern African Development Community, congratulated Tshisekedi on Sunday and called for a peaceful handover of power.Tshisekedi's victory was provisionally announced earlier this month by the election commission CENI, but it was challenged both at home and abroad.The Financial Times and other foreign media have reported seeing documents that confirm Fayulu as the winner, and the influential Roman Catholic Church, which says it deployed 40,000 observers to monitor the poll, has also dismissed the official outcome.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.