Nigerians widely criticised the country's first local elections since the end of military rule five years ago, citing fraud, intimidation and violence which has resulted in nearly 50 deaths.
Observers and witnesses said fraud was rampant in Saturday's polls in which thousands of local government posts were at stake, giving the winners access to a share of the nation's oil export earnings distributed by the federal government.
"I had hoped to see less violence in this election, but my hopes were dashed," Anyakwee Nsirimovu, a Nigerian observer with the non-governmental organisation Transition Monitoring Group, said on Sunday.
"We did not go through all the trouble of fighting the military to have a bunch of autocrats running a civilian government," he said, adding seven people had been shot or macheted to death in the oil-rich Rivers state.
Sunday newspapers reported a further seven killed on Saturday in four states in the south of the oil exporting country, bringing to 47 the number killed in two days of violence.
President Olusegun Obasanjo, who has led Nigeria since the end of the military rule, won a second term last year in elections described by the US State Department as "marred by serious irregularities and fraud including political violence".