Alassane Ouattara, the declared winner of the presidential election, casts his ballot. (Photo Courtesy UN Photo/Basile Zoma)

Cote d'Ivoire's electoral commission has announced that opposition candidate Alassane Ouattara has won the nation's long awaited presidential election.

The BBC reported that Ouattara defeated President Laurent Gbagbo with 54 percent of the vote.

The Constitutional Court has contested the announcement. Gbagbo's supporters have claimed there was electoral fraud in the north of the country where Ouattara draws most of his support and where the former New Forces rebel group is based.

Tension has been rising in Cote d'Ivoire, Africa's largest cocoa producer, since announcement of the results was delayed. In an attack on an office of Ouattara's Rally of the Republicans party, at least four people were shot dead on Wednesday night, the BBC said.