* More than 100 sites blocked for "maintenance"
* Source says this is trial run of bid to silence critics before poll
* Veteran leader Rakhmon brooks little dissent, seeks new term
Tajikistan blocked access to more than 100 local and foreign websites on Tuesday, in what a government source said was a rehearsal of silencing critics before next year's election when President Imomali Rakhmon will again run for office.
Rakhmon, a 60-year-old former head of a Soviet cotton farm, has ruled the impoverished Central Asian nation of 7.5 million for 20 years. He has overseen constitutional amendments that allow him to seek a new seven-year term in November 2013.
The Internet remains the main platform where Tajiks can air grievances and criticise government policies at a time when the circulation of local newspapers remains tiny and television is tightly controlled by the state.
Tajikistan's state communications service blocked 131 Internet sites "for technical and maintenance works".
"Most probably, these works will be over in a week," Tatyana Kholmurodova, deputy head of the service, told Reuters. She declined to give the reason for the work, which cover even some sites with servers located abroad.
The blocked resources included Russia's popular social networking sites www.my.mail.ru and VKontakte (www.vk.com), as well as Tajik news site TJKnews.com and several local blogs.
"The government has ordered the communications service to test a possibility of blocking dozens of sites at once, should such a need arise," a senior government official told Reuters on condition of anonymity.
"It is all about November 2013," he said, in a clear reference to the presidential election.
Other blocked websites included a Ukrainian soccer site, a Tajik rap music site, several local video-sharing sites and a pornography site.
Predominantly Muslim Tajikistan, which lies on a major transit route for Afghan drugs to Europe and Russia, remains volatile after a 1992-97 civil war in which Rakhmon's Moscow-backed secular government clashed with Islamist guerrillas.
Rakhmon justifies his authoritarian methods by saying he wants to oppose radical Islam. But some of his critics argue repression and poverty push many young Tajiks to embrace it.
Tighter Internet controls echo measures taken by other former Soviet republics of Central Asia, where authoritarian rulers are wary of the role social media played in revolutions in the Arab world and mass protests in Russia.
The government this year set up a volunteer-run body to monitor Internet use and reprimand those who openly criticise Rakhmon and other officials.
In November, Tajikistan blocked access to Facebook, saying it was spreading "mud and slander" about its veteran leader.
The authorities unblocked Facebook after concern was expressed by the United States and European Union, the main providers of humanitarian aid for Tajikistan, where almost a half of the population lives in abject poverty.
Asomiddin Asoyev, head of Tajikistan's association of Internet providers, said authorities were trying to create an illusion that there were no problems in Tajik society by silencing online criticism.
"This is self-deception," he told Reuters. "The best way of resolving a problem is its open discussion with civil society."