Independent election monitors in Russia have said they are coming under increasing pressure from the authorities ahead of a parliamentary election tomorrow.

The complaint came after the leader of the monitoring group Golos, Lilya Shibanova, was detained for 12 hours at a Moscow airport as she arrived for the poll.

Yesterday, the organisation was fined for allegedly violating election law.

Russian MPs have questioned why Golos is allowed to monitor the country's elections.

The group is a non-party political watchdog, largely funded by the European Union and the United States.

Russians in the Far East have begun voting Sunday in key parliamentary elections expected to hand victory to Vladimir Putin's party amid claims of campaign fraud and the unprecedented intimidation of observers.

"Polling stations are open," Konstantin Mikhailov, head of the local election commission in the city of Anadyr in the resource-rich Chukotka region, told AFP.

The other regions to vote first are diamond-mining Yakutia, the region of Sakhalin which includes an island chain contested by Japan, Kamchatka, and Magadan, the site of Soviet-era Gulag camps.

Seven parties, including Mr Putin's ruling United Russia, are running in the elections to the lower house of parliament, the 450-deputy State Duma.

It is seen as a dry run of presidential polls in March in which current Prime Minister Putin is expected to win back his old job.

Analysts say United Russia had initially hoped to repeat the success of last parliamentary elections in 2007 when it secured a landslide majority of 64.3% and received 315 seats in the Duma.

But with support for Mr Putin and his party crumbling, United Russia is expected to win just over half the vote, according to pollsters.