The central Asian country of Kyrgyzstan will choose a new president on Sunday in elections that are unusual in the region for being unpredictable.
One of the front runners, Sooronbai Jeenbekov, is backed by outgoing leader Almazbek Atambayev, who is reaching the end of a six-year term.
He and the other favourite, Omurbek Babanov, are former prime ministers.
Western diplomats are “inclined to believe” the election will be free and fair, says a BBC correspondent.
But since the beginning of the campaign, there have been numerous reports of violations by various candidates.
Kyrgyzstan, which has been independent since the fall of the Soviet Union, is a nation of six million people. Its first two post-Soviet presidents were swept from power by popular discontent.
The poll is historic because for the first time in the history of Kyrgyzstan an elected president is due to peacefully hand over power after the election, says BBC Central Asia reporter Abdujalil Abdurasulov.
However, the election been overshadowed by a row over alleged interference from neighbouring Kazakhstan.
Mr Atambayev angered Astana by saying Mr Babanov, a charismatic businessman who made his money there, was the Kazakh choice for the new president. He has denied that he is backed by them.
In response Kazakhstan tightened customs checks at the border, leading to long queues.
The country’s presidents are restricted to a single six-year term under a constitution that has been in force since 2010.