Kenyans are casting ballots in their country's presidential election, bringing to a close yet another turbulent campaign season in the economically vital East African nation.

Voters began lining up hours before dawn Tuesday to cast their ballots in hotly contested nationwide polls. One voter, 31-year-old Mildred Malubi, said she waited in line for three and a half hours to vote in Kangemi slum, in Nairobi.

This year's election is the second consecutive election between the incumbent, 55-year-old Uhuru Kenyatta, and his longtime rival, 72-year-old Raila Odinga, who is making his fourth run for the presidency. Kenyatta has the support of Kenya's majority Kikuyu ethnic tribe, while Odinga is favored by ethnic Luo people.

The campaign has been marred by accusations of vote rigging made by Odinga against the president, and the murder of a top-ranking election official. The heightened tensions have raised concerns of a repeat of the disputed 2007 vote, when more than 1,100 were killed and 600,000 more displaced in a wave of ethnic violence.

Former U.S. President Barack Obama, whose father was born in Kenya, issued a statement Monday calling on all Kenyans to "reject violence and incitement."

"I urge all Kenyans to work for an election — and aftermath — that is peaceful and credible, reinforcing confidence in your new Constitution and the future of your country," Obama wrote.

Thousands of election observers have been deployed throughout Kenya, including former U.S. Secretary of State John Kerry.

The polls close at 5 pm local time. Results are expected by Friday.

肯尼亞選民開始總統大選投票，讓這個東非重要國家又一場緊張騷動的選戰進入尾聲。

選民們星期二天亮前好幾個小時就開始在投票站外排隊等候，在這次競爭異常激烈的選戰中投下自己的一票。一個31歲的選民說，他在內羅畢坎吉米貧民窟的投票站外排了三個半小時的隊。

這是55歲現任總統肯雅塔和他的長期政敵，72歲的奧廷加之間連續第二次較量，也是奧廷加第四次參選總統。肯雅塔得到了肯尼亞占人口多數的基庫尤族人的支持，而奧廷加則深受盧奧族人的愛戴。

奧廷加指責肯雅塔總統在選舉中有舞弊行為，外加一名負責選舉事務的高級官員被謀殺，都給這次大選帶來了瑕疵。緊張局勢的加劇讓外界擔心，2007年選舉糾紛引起的民族暴力會重演，那一輪暴力共造成1100多人被殺，60多萬人流離失所。

美國前總統奧巴馬的父親出生在肯尼亞。奧巴馬星期一發表聲明，呼吁所有肯尼亞人“拒絕暴力和煽動”。

奧巴馬寫道：“我敦促所有肯尼亞人，為和平可信的選舉和選舉后續工作努力，鞏固對你們的新憲法和你們國家未來的信心。”

數千名選舉觀察員前往肯尼亞各地監督選舉，其中也包括美國前國務卿克里。

投票站定于當地時間下午五點關門。選舉結果預計星期五公布。

Kenyans are casting ballots in their country's presidential election, bringing to a close yet another turbulent campaign season in the economically vital East African nation.

Voters began lining up hours before dawn Tuesday to cast their ballots in hotly contested nationwide polls. One voter, 31-year-old Mildred Malubi, said she waited in line for three and a half hours to vote in Kangemi slum, in Nairobi.

This year's election is the second consecutive election between the incumbent, 55-year-old Uhuru Kenyatta, and his longtime rival, 72-year-old Raila Odinga, who is making his fourth run for the presidency. Kenyatta has the support of Kenya's majority Kikuyu ethnic tribe, while Odinga is favored by ethnic Luo people.

The campaign has been marred by accusations of vote rigging made by Odinga against the president, and the murder of a top-ranking election official. The heightened tensions have raised concerns of a repeat of the disputed 2007 vote, when more than 1,100 were killed and 600,000 more displaced in a wave of ethnic violence.

Former U.S. President Barack Obama, whose father was born in Kenya, issued a statement Monday calling on all Kenyans to "reject violence and incitement."

"I urge all Kenyans to work for an election — and aftermath — that is peaceful and credible, reinforcing confidence in your new Constitution and the future of your country," Obama wrote.

Thousands of election observers have been deployed throughout Kenya, including former U.S. Secretary of State John Kerry.

The polls close at 5 pm local time. Results are expected by Friday.

肯尼亞選民開始總統大選投票，讓這個東非重要國家又一場緊張騷動的選戰進入尾聲。

選民們星期二天亮前好幾個小時就開始在投票站外排隊等候，在這次競爭異常激烈的選戰中投下自己的一票。一個31歲的選民說，他在內羅畢坎吉米貧民窟的投票站外排了三個半小時的隊。

這是55歲現任總統肯雅塔和他的長期政敵，72歲的奧廷加之間連續第二次較量，也是奧廷加第四次參選總統。肯雅塔得到了肯尼亞占人口多數的基庫尤族人的支持，而奧廷加則深受盧奧族人的愛戴。

奧廷加指責肯雅塔總統在選舉中有舞弊行為，外加一名負責選舉事務的高級官員被謀殺，都給這次大選帶來了瑕疵。緊張局勢的加劇讓外界擔心，2007年選舉糾紛引起的民族暴力會重演，那一輪暴力共造成1100多人被殺，60多萬人流離失所。

美國前總統奧巴馬的父親出生在肯尼亞。奧巴馬星期一發表聲明，呼吁所有肯尼亞人“拒絕暴力和煽動”。

奧巴馬寫道：“我敦促所有肯尼亞人，為和平可信的選舉和選舉后續工作努力，鞏固對你們的新憲法和你們國家未來的信心。”

數千名選舉觀察員前往肯尼亞各地監督選舉，其中也包括美國前國務卿克里。

投票站定于當地時間下午五點關門。選舉結果預計星期五公布。