* FSB calls for access to Gmail, Hotmail and Skype
* Cyber attack temporarily shuts top Russian blogging site
By Thomas Grove
MOSCOW, April 13 (Reuters) - Russian hacker attacks on the country's biggest blog site and a spy agency's warning to Gmail and Skype have raised fears that authorities are tightening their grip on dissent in a China-like assault on free speech.
With an eye on Arab unrest that has toppled two North African leaders and spurred Western military intervention in Libya, Moscow is keen to defuse potential turmoil ahead of a December parliamentary election and a 2012 presidential vote.
In a country where much media is state-run, the Internet is one of the last bastions of free speech. Russian bloggers freely criticize authorities, often scathingly, question high-level corruption and swap information without fear of censorship.
But the price of open dissent on the Internet may be too high ahead of next March's presidential election that could see Prime Minister Vladimir Putin, who served as president in 2000-2008, sweep back into Russia's top seat of power.
"People close to the government believe the Internet will be more crucial in the upcoming elections than traditional media," said Andrei Soldatov, head of the think-tank Agentura.ru.
The Internet has played a crucial role in the unrest that has rocked Northern Africa and the Middle East, prompting some governments to shut it down. Similar turmoil is unlikely in Russia, but authorities want to be prepared for the worst.
Last week, nearly five million bloggers -- including President Dmitry Medvedev -- were left in the dark due to a cyber attack that temporarily closed top Russian blogging site Live Journal www.livejournal.ru.
"This is a test drive during a very important year to see if it's possible to close down web sites, in particular social networking sites in case of demonstrations," Soldatov said.
Putin and his protege Medvedev both enjoy approval ratings of nearly 70 percent, but their popularity has eased, partly on perceptions that vast revenues from high oil prices are not reaching the population. They have said they will decide together which of them will stand for election in 2012.
The United States, itself wary of Russian and Chinese cyber attacks, said in its 2010 human rights report that Internet systems route Russian web traffic to the Federal Security Services (FSB), the main successor to the Soviet-era KGB.
The head of the FSB special communications center, Alexander Andreyechkin, said last week uncontrolled use of Gmail, Hotmail and Skype were "a major threat to national security" and called for access to the encrypted communication providers.
The Web search leader has clashed with China over Internet censorship and last month accused the Chinese government of making it difficult for Gmail users to access the service.
The FSB declined comment when contacted by Reuters.
The mastermind behind the latest cyber attacks has been a subject of speculation. Russian hackers are often contracted out by security organs to carry out attacks inside and outside the country, said Agentura's Soldatov in a book he co-authored, 'The New Nobility'.
The Live Journal site was brought down by a denial of service attack -- a tried and tested method of disrupting websites by flooding their servers with requests.
Chechen separatists and the Georgian and Estonian governments have been high-profile victims of similar attacks in the past. Supporters of WikiLeaks also used this method to attack organizations that blocked support for WikiLeaks.
A study released last month by internet research firm Comscore found that Russians are the world's most active social networking users, with visitors spending an average of 9.8 hours on social networks monthly, more than double the global average.
Overall use of the Internet has also soared over the past decade. Some 43 percent of Russians regularly use it today, up from just 6 percent in 2002, said Public Opinion Foundation, an independent Russian pollster.
Many in Russia's blogging community, outraged by the hacker attacks, remain defiant.
"It doesn't matter whether or not they close Facebook, Twitter or other popular means of communication," said user Viktor Korb on his Live Journal blog late last week.
"They will never realize that the more they forbid and pressure, the more they will suffer a blowback from their actions," he wrote. (Additional reporting by Alissa DeCarbonnel and Georgina Prodhan; editing by Gareth Jones)