The exit polls from Sunday's election in Ukraine's presidential run-off have shown a bias toward pro-Russian opposition leader Viktor Yanukovich.

Mr Yanukovich appears to have beaten pro-Western Prime Minister Yulia Tymoshenko by just a few percentage points.

Ms Tymoshenko, who complained of electoral fraud in the run-up to the election, has said the difference is too small to indicate a winner.

She has pledged to contest the result if no clear winner emerges.

About 36 million Ukrainians were eligible to vote for a successor to incumbent president Viktor Yushchenko, who was swept to power in 2004 after mass demonstrations against electoral fraud turned into the Orange Revolution.