* Kyrgyzstan opposition leader in Russia
* Opposition gearing up for nationwide protests on Wednesday
* Kyrgyzstan rejects OSCE criticism
(Adds details, CEC, OSCE quotes)
By Olga Dzyubenko
BISHKEK, July 27 (Reuters) - Kyrgyzstan's opposition leader flew to Moscow on Monday to try to win support in his standoff with President Kurmanbek Bakiyev following last week's disputed election in the Central Asian nation.
The ex-Soviet Muslim republic is at the heart of Russia-U.S. rivalry in the vast region stretching between Afghanistan, Iran, China and Russia. Courted by both Moscow and Washington, it now hosts a Russian and a U.S. military air base.
The vote, condemned as rigged by the opposition, has stirred up tensions in Kyrgyzstan at a time when the West is concerned with the spread of Islamist militancy from Afghanistan.
Official results gave Bakiyev 76 percent of the vote while opposition challenger Almazbek Atambayev got 8 percent.
Russia largely supports Bakiyev's rule and has made it clear it is in favour of his re-election, particularly after he agreed this month to discuss allowing Russia to open another military facility in Kyrgyzstan.
On Monday, Atambayev was in Moscow to discuss the vote but officials were tight-lipped on the nature of his visit and Russia's Foreign Ministry said it was unaware of his visit.
"He has gone to Moscow ... to talk about what happened in Kyrgyzstan on July 23," said Atambayev's campaign chief Bakyt Beshimov, adding that he could not reveal whom Atambayev was meeting in Moscow. "They are holding discussions."
Other officials at Atambayev's camp told Reuters he was in Moscow to share his concerns on the conduct of the election but also refused to say whom he was meeting.
PREPARING FOR PROTESTS
Russian President Dmitry Medvedev has yet to congratulate Bakiyev on his victory. Neither Russia nor the United States has explicitly commented on the conduct of the election.
However, in a move that has galvanised the long-fragmented opposition, the Organisation for Security and Cooperation in Europe has criticised the vote, saying its monitors witnessed widespread cases of ballot box stuffing and multiple voting.
The opposition is gearing up for nationwide protests from Wednesday to demand a repeat vote. A Muslim nation where the average monthly wage is just $120, Kyrgyzstan has a history of unrest that has worried the West.
In 2005, violent protests toppled its previous president and brought Bakiyev to power -- events that were followed shortly by a bloody rebellion in neighbouring Uzbekistan.
The authorities promise to crack down on any illegal forms of protest. "If they do not have permission then we will act within the framework of law," said an Interior Ministry spokesman. "We will prevent all unlawful actions."
Security remains a major concern for the West and Russia who see Kyrgyzstan as key to their efforts to maintain stability in Central Asia, a region where officials say that Taliban-linked rebels are increasingly active.
Over past months, Kyrgyz forces have engaged in a series of gun battles with what the government has described as Islamist militants in the southern Ferghana valley.
The election, criticised by the European Union, puts the United States in a potentially awkward position in Central Asia after Washington agreed to pay $180 million this year to keep open its air base in Kyrgyzstan.
Kyrgyzstan has rejected Western criticism of the vote and accused the Organisation for Cooperation and Security in Europe of failing to present evidence of any electoral fraud.
"The CEC has asked the OSCE mission to present data on violations but the request was rejected," Lyubov Shereshkova, a CEC official, told a commission meeting. "Therefore the CEC views the OSCE/ODIHR statement in critical light."
The OSCE said it was not part of its role to share such evidence. "We are not election police," said a spokesman for the OSCE's ODIHR election monitoring arm. "It is the role of Kyrgyzstan's authorities to follow up on any allegations." (Writing by Maria Golovnina; Editing by Alison Williams)