Kenyans on Tuesday voted in large numbers an election that pits President Uhuru Kenyatta against challenger Raila Odinga in this East African economic hub as well as the ethnic allegiances that shadow its democracy.

Voters formed long lines at many polling stations before dawn, waiting for the chance to cast ballots in the tightly contested race for the presidency as well as for more than 1,800 elected positions, including governors, legislative representatives and county officials. A key concern was whether Kenya would echo its 2013 election, a mostly peaceful affair despite opposition allegations of vote-tampering, or the 2007 election, which led to violence fueled by ethnic divisions that killed more than 1,000 people.

Kenyatta, the 55-year-old son of Kenya's first president after independence from British colonial rule, campaigned on a record of major infrastructure projects, many backed by China, and claimed strong economic growth. Odinga, 72, is also the son of a leader of the independence struggle and has cast himself as a champion of the poor and a harsh critic of endemic corruption in many state institutions.

However, many voters are expected to vote along ethnic lines. President Kenyatta is widely seen as the candidate of the Kikuyu people, the country's largest ethnic group. Odinga is associated with the Luo voting bloc, which has never produced a head of state.

More than 300 people, including ethnic Maasai draped in traditional red blankets, waited for hours in the dark before polling station opened in the Rift Valley town of Il Bissil. Kenyan television also showed long lines of voters in the port city of Mombasa.

"This is a positive feedback for us," polling official James Njaya said of the high turnout in Kibera, a poor area in Nairobi, the Kenyan capital.

Like many Kenyan voters, 34-year-old Fred Nyakundi arrived at a polling station several hours before it opened and waited in line in the dark before casting his vote.

"The exercise is very slow, but I am happy with the service I got," said Nyakundi, who owns a carpentry business in Nairobi. "I am going home to open the business and wait for results."

Another voter, 41-year-old Fatuma Ramadhan, thought the voting procedure was speedy. She was able to vote at 6 a.m., when polling stations opened, and then opened her restaurant to serve breakfast to other voters