Updated

Russia's elections commission head says results from voting for parliament in a Siberian region could be annulled if allegations of vote fraud there are confirmed.

Ella Pamfilova's statement came Sunday as Russians cast ballots for the State Duma, the lower house of parliament.

The pro-Kremlin United Russia party is expected to retain its dominance and the three other largely cooperative parties in the current parliament are also expected to win seats.

Russian officials are concerned that widespread allegations of vote fraud could spark protests similar to the massive demonstrations after elections in 2011.

A candidate from the liberal Yabloko party in the Altai region of Siberia told state news agency Tass that young people were voting in the name of elderly people unlikely to come to polling stations.