Russians cast votes Sunday across nine time zones, in parliamentary polls that have been plagued by claims of campaign fraud and intimidation of election monitors.

The elections are widely expected to hand victory to Vladimir Putin's ruling United Russia Party, which held a two-thirds majority in the outgoing State Duma (lower house of parliament). But analysts in recent weeks said that majority could shrink significantly in the current polls, as voters voice discontent about the growing income gap between Russia's rich and poor and allegations of official corruption.

For his part, Mr. Putin has accused unnamed Western governments of seeking to undermine Sunday's polls as well as presidential elections that he is expected to win in March 2012.

On Sunday, a leading independent Russian vote monitoring organization, Golos, told VOA that Russian police have blocked poll watchers from their monitoring posts around the nation. Golos and the popular Russian opposition radio station Echo of Moscow (Ekho Moskvy) also said their websites were crippled by denial-of-service attacks, which overload websites and make them inaccessible. Several opposition news sites also were not working.

Golos says it has compiled more than 5,300 complaints of election law violations, and it accused the ruling party of complicity in most of them.

Last week, Mr. Putin, the current prime minister, formally accepted his party's nomination to return to the presidency – a post that analysts say he is certain to win. He announced his intentions in September, confirming a deal under which he would appoint current President Dmitry Medvedev as his prime minister.

The planned job swap has angered many in Russia, who said it would strengthen authoritarian rule and clear the way for Mr. Putin to become Russia's longest-serving leader since communist times.

If he regains the presidency, the 59-year-old Mr. Putin could serve two more 6-year terms and remain in power until 2024.