Voters Russia are casting ballots in parliamentary elections that are expected to favor Prime Minister Vladimir Putin's United Russia party.

Polling stations opened starting in the Russia's far east.

The voting Sunday comes amid claims of campaign fraud and unprecedented intimidation of observers.

Members of Russia's only independent election monitoring group say their leader Lilya Shibanova was detained for 12 hours Saturday at a Moscow airport.

Customs officials held the Golos monitoring group leader at Moscow's Sheremetyevo airport after she refused to hand over her laptop to security officers who said they wanted to inspect the computer for illegal software. Shibanova was released after she handed over the computer.

She told reporters in St. Petersburg Saturday she feared that her organization would not be allowed to properly monitor the elections.

“From my point of view, there is one major threat. The threat is that tomorrow (December 4) we start to do our job and do our best to do our program (of monitoring the elections) and then we hear in the morning that they don't let us in (the polling stations).

But the group says it is determined to go to the polls Sunday.

The airport detention is just the latest incident of intimidation of Golos in the run-up to the elections. On Friday, a Moscow court fined the monitoring group about $1,000 for compiling election law violations and posting them online. Golos, has nearly 5,000 complaints of alleged violations that it has received via text message, e-mail and telephone. Friday night, state-run television aired a program attacking the group.

Golos public relations manager Dmitry Merezhko told VOA that the group will protest the court decision, but not until it is done monitoring the vote.

He said Golos has recently received more public support in response to the media coverage.

The last polling places are scheduled to close at 1700 hours GMT.