Russian Political Sites under DDOS cyber attack during the Country's Parliamentary elections. DDOS attack hits Russian radio station Moscow Echo and election-monitoring group Golos, the website of opposition weekly New Times as well as several other sites on Sunday.
"The attack on the website on election day is clearly an attempt to inhibit publication of information about violations," Moscow Echo editor-in-chief Alexei Venediktov wrote on Twitter.
Golos said it was the victim of a similar "distributed denial of service" (DDoS) attack, while several other opposition news sites were down. The Moscow Echo is popular among the liberal opposition although it is owned by state gas giant Gazprom.
After the close of polls on Sunday, the Moscow Echo website was working again but the Golos website was still inaccessible.
Prime Minister Vladimir Putin, whose United Russia party is expected to win Sunday's polls but with a reduced majority, has denounced non-governmental organisations like Golos, comparing them to the disciple Judas who betrayed Jesus.
Russia has seen an upsurge in Internet penetration since the last elections in 2007, and analysts have said the explosion of critical material on the web poses one of the biggest challenges to United Russia's grip on power.
Golos said on Twitter that its main website as well as the "Map of Violations" site detailing claims of fraud across Russia were under "massive DDoS attacks".
Golos head Liliya Shibanova said the authorities seemed especially angry at their Map of Violations project, where people could upload any information or evidence of election violations.
"It's a very expensive operation," Shibanova said of the attacks. "It's a big organisation with plenty of means that must have done it."
Shibanova, who was held for nearly 12 hours Saturday by customs officials who also confiscated her computer, said the attack consisted of 50,000 hits per second by computers attempting to access the Golos website.
The website of opposition weekly New Times, known to publish investigative reports about government officials and feature columns by jailed oil tycoon Mikhail Khodorkovsky was inaccessable for several hours Sunday.
Business daily Kommersant was not working for the fourth consecutive day after it was hacked on Thursday. Hackers switched its IP address.
Moscow Echo filed a complaint to the Central Election Committee demanding to open a criminal case into the attacks, and editor Venediktov said he complained directly to the spokespeople of Putin and President Dmitry Medvedev.
The radio station is popular with the liberal opposition, though it is owned by the media arm of state-controlled Russian gas giant Gazprom.
"Any hacker attack on any resource leads to financial losses, which is essentially the same as stealing," said the chairman of Moscow Echo's board of directors Nikolai Senkevich, adding that Gazprom's media holding "fully supports" the station's concern.
Pro-Kremlin youth activists also complained on Twitter that the opposition ordered an attack on their website chronicling violations by the opposition parties, although the website was fully accessible.
Russian bloggers also complained of their inability to access their accounts on popular blogging platform Livejournal.com. The website has been a victim of repeated DDoS attacks throughout the week and worked intermittently.
"The goal of the attackers is clear," Anton Nossik, the media director of Livejournal owner SUP, wrote on his blog, alleging that the perpetrators are a "group of criminals" who are "probably fattened by the federal budget."