The elections, in which ethnicity and the country's north–south divide played a crucial role, ultimately pitted President Gbagbo, who had a strong support base in the south, against the long-time opposition leader and former Prime Minister Ouattara, who had overwhelming support in much of the north. The events leading up to the second round and following it were characterized by serious tension and some incidents of violence, and the preliminary report of the Carter Center "cautions against a rush to judgment regarding the overall credibility of the election", but most observers considered that the overall result was not compromised, and that the elections were essentially free and fair. On 2 December 2010, the Independent Electoral Commission (IEC) released provisional results showing that Ouattara had won the elections in the second round with 54% of the vote. However the President of the Constitutional Council (CC) immediately declared that the results were invalid and the next day, in accordance with article 94 of the Constitution, the Constitutional Council declared Gbagbo the winner. Both Gbagbo and Ouattara claimed victory and took the presidential oath of office. The ensuing events led to the 2010–2011 Ivorian crisis.