A supporter of the Orange Democratic Party holds up a machete in front of a burning barricade during riots in the Kibera slum in Nairobi. Kenya's opposition declared victory Saturday in the presidential election on the basis of partial results, but authorities cautioned that not all votes had been counted and appealed for patience. Tensions over the vote erupted into violence in Nairobi and opposition strongholds.

Nairobi, Kenya ? Thousands of Kenyans enraged over delays in announcing the country’s next president burned down homes and attacked political rivals with sticks and machetes on Saturday, tainting a vote that initially was seen as a beacon of hope for democracy in Africa.

Three people were shot dead during protests in Migori, 360 miles west of Nairobi, said area police chief Grace Kaindi. In the capital Nairobi, hundreds of supporters of opposition candidate Raila Odinga marching on the electoral commission were beaten back by police using tear gas.

With votes in 180 of 210 constituencies counted, Odinga clung to his razor-thin lead by 38,000 votes. Despite pleas from both parties to release final results quickly, electoral commission chairman Samuel Kivuitu suspended announcing tallies for the night, promising to look into allegations of rigging from both sides.

“If they don’t announce results in two hours, we are going to burn this place down!” shouted 23-year-old John Odhiambo as youths armed with metal rods looted a flaming market behind him in the capital’s biggest slum, Kibera.

Police Commissioner Hussein Ali appealed for calm.

“There cannot be democracy where people think they can get recourse through hooliganism,” he said.

Thursday’s vote pitted incumbent President Mwai Kibaki against Odinga, a flamboyant millionaire who cast himself as a champion of the poor. It was the country’s most closely fought election since independence from Britain in 1963. On Saturday, both parties said they had won but the electoral commission said counting was not finished yet.

Kibaki is from Kenya’s largest ethnic group, the Kikuyu, while Odinga is from the second largest group, the Luos, who are poorer and feel politically marginalized.

Odinga, a fiery 62-year-old former political prisoner, promised change and help for the poor.

His main constituency is Kibera, home to at least 700,000 people who live in extreme poverty and the scene of many of Saturday’s riots. In recent months he has made it a priority to reach out to the country’s middle class and businessmen, many of whom are Kikuyus.

Supporters of 76-year-old Kibaki say he has turned Kenya’s moribund economy into an East African powerhouse, with an average growth rate of 5 percent and a booming tourism industry. But Kibaki’s anti-graft campaign has been seen as largely a failure, and the country still struggles with tribalism and poverty.

Odinga’s Orange Democratic Movement party accused the government of deliberately delaying results because they were losing. Kibaki’s Party of National Unity insists it wants the results released quickly, but says it has a list of grievances it wants addressed.