Abidjan: The campaign for the November 28 runoff vote for the Ivory Coast presidency officially kicks off on Saturday with incumbent Laurent Gbagbo facing a stiff challenge from rival Alassane Ouattara.
Fighting broke out between youths supporting the rival candidates on Friday, leaving about 20 people injured including two police officers, according to the police.
Some 300 students supporting Gbagbo gathered near the headquarters of the coalition backing his opponent Alassane Ouattara, and the two groups, some armed with batons and clubs, started throwing stones and other items at each other.
More than 50 members of the security forces stepped in and used tear gas to stop some youths from trying to enter the rival coalition`s headquarters, a report said.
Police attributed the violence to people close to Ouattara`s coalition, in a statement read on state television late Friday.
Interior Minister Desire Tagro appealed for calm, according to the police.
The confrontation between opposing sides was the first of this size in the high-stakes election campaign which began before the first round held on October 31.
Late Friday afternoon, a group of young Ouattara supporters left their coalition`s headquarters and headed towards the Gbagbo supporters, but police stopped them and fired tear gas.
On Saturday, Gbagbo is to hold a rally in Agboville, 80 kilometres (50 miles) north of Abidjan, while former prime minister Ouattara will meet supporters in the economic capital.
Gbagbo, a political strongman who has ruled the country for five years since the expiry of his term in 2005, took 38 percent of the vote in the October 31 first round while Ouattara took 32 percent, meaning neither secured an outright majority.
The bitter personal history between the two men raised concerns of a fierce second-round of stumping compared to the first-round vote, which saw a high turnout of 83 percent in a generally peaceful environment with electoral observers reporting only minor voting infringements.
The vote is aimed at ending a decade of crisis in the west African country, which has seen civil war and elections cancelled six times in the past five years.
Ivory Coast`s economy has suffered in the upheaval, squandering the gains made during the "Ivorian miracle" brought about by "father of the nation" Felix Houphouet-Boigny, ruler from independence from France in 1960 to his death in 1993.