The most bitterly fought presidential election in Ukraine's post-Soviet history reaches its climax today, with voters choosing between the pro-western liberal Viktor Yuschenko and Moscow-backed prime minister Viktor Yanukovych.
Opposition leaders said they had little faith the votes would be fairly counted, and have called for a massive rally in central Kiev after the polls close.
'The tensions whipped up around this election are unprecedented, and there is real possibility of turmoil,' said Oleksandr Dergachov, an expert with the independent Institute of Political and Ethno-National Studies in Kiev.
'The population is so polarised that a struggle over the legitimacy of the results seems inevitable.'
The latest surveys suggest a dead heat, with Mr Yanukovych at 34 per cent and Mr Yuschenko at 32 per cent.
If neither wins an outright majority today, they will face each other in a run-off on November 21.
Opposition workers said opinion polls published in the state-dominated media were as fraudulent as they expected the official vote-counting to be on election day, and insisted a majority of Ukrainians secretly backed Mr Yuschenko.