"He held parliamentary elections in 2007, which effectively removed any significant opposition from the parliament, so they effectively say yes to all of his policies and vote him through," he said.

"That's left the political opposition without much to hold on to. They've been trying to mount a campaign since the end of last year to try to force the president to return to a more democratic mandate."

Opposition complaints

Elected in 2005 in a poll seen as free and fair by Western observers, Bakiev has been accused by the opposition of becoming increasingly repressive and curtailing civil liberties.

In depth


 Opposition fears in Kyrgyz election

Bakiev's steps to tighten his grip on power and a string of mysterious attacks on politicians and journalists in the run-up to the election have caused concern among voters.

As the voting began, the opposition accused Bakiev of fraud and vowed to stage protests.

Police fired in the air and used batons to break up a group of activists who rallied against what the opposition described as election fraud, the opposition and a local official said.

"The government has lost these elections, it is now about how they will rig the results," Almazbek Atambayev, the main opposition challenger from the Social Democratic party, told the Reuters news agency ahead of the vote.

"If they try to steal votes on the election day, anything may happen."

The government said it was doing everything to ensure the vote was fair and transparent.

Rising tensions

Thursday's poll will also be watched closely for any signs of unrest that could disturb peace in Central Asia, given the country's strategic location for US-led military efforts against the Taliban in neighbouring Afghanistan.

Analysts say Kyrgyzstan's stability is vital to the region's.

The country and region have been largely peaceful since 2005 but tensions have risen in recent weeks with some analysts saying intensified fighting in nearby Afghanistan and Pakistan may have led to some Taliban fighters of Central Asian origin returning to the region.

The Manas airbase is used as a hub for US-led military operations in Afghanistan [Reuters]

In the past months, Kyrgyz forces have engaged in gun battles with fighters that the authorities describe as Islamist rebels but critics accused Bakiev of using the excuse of an Islamist threat in the mostly Muslim nation to bolster his re-election chances and win concessions from the US and Russia.

Security was tight across Kyrgyzstan ahead of the vote, with 5,000 officers on high alert and extra measures enforced in the border areas.

The interior ministry said on the eve of the vote that its forces had confiscated more than 300 illegal guns and ammunition in special operations across the country.

Kyrgyzstan's proximity to Afghanistan has propelled it to the forefront of Russian-US rivalry in Central Asia, with both Moscow and Washington operating military bases in its mountainous territory.

Bakiev seems to have exploited that rivalry, telling the US earlier this year to get out from its airbase in Manas, which is crucial to US operations in Afghanistan, after receiving more than $2bn in aid and loan guarantees from Moscow.

But the US was in June allowed to stay after agreeing to pay three times more rent to Kyrgyzstan, from $17.4m to $60m a year.