Voting has been extended in Georgia's parliamentary election after thousands of people complained that they had not had time to cast their ballots.
Many people were not registered to vote in areas where the opposition was likely to do well.
In the capital Tbilisi and the city of Kutaisi, where support for the government bloc is low, several polling stations did not open at all. The authorities said this was because voter lists were incorrect.
An improvised open-air ballot box is used in Kadzhori, north of Tbilisi
Voting has now been extended in the two cities.
The election is being seen as a referendum on the presidency of the former Soviet foreign minister, Eduard Shevardnadze.
Most Georgians say they are fed up with the current regime, blaming it for widespread poverty in the once affluent former Soviet republic, where corruption is rife.
Pre-election polls indicated that opposition parties would gain large numbers of seats.
The authorities announced on Sunday they had found a significant cache of weapons near Tbilisi, which they said were intended for use in an attack on President Shevardnadze.
Security Minister Valeri Khaburdzania said the find included anti-tank grenades and large amounts of explosives.
He said they had information to show there was a plan to detonate the explosives along the route used by the president's motorcade.
There have been two previous attempts to assassinate Mr Shevardnadze - in one incident his armoured car was hit by anti-tank grenades.
Opposition groups have warned they will hold massive demonstrations if they find evidence that the vote has been rigged.
Hundreds of special forces are gathering around Tbilisi to prevent unrest.
President Shevardnadze: Struggling to tackle poverty
The World Bank estimates that more than half the country's population lives below the poverty line.
Angry voters at a polling station in central Tbilisi demanded to know why they were not being allowed to vote on Sunday.
A handwritten note on the door said simply "vote cancelled".
Mikhail Saakashvili, the leader of a prominent opposition party, told reporters he was turned away from his polling station in Tbilisi because he had not been registered to vote.
Gia Nodia, director of the Caucasus Institute for Peace, Democracy and Development in Tbilisi, said: "I was on the list two weeks ago, but this morning my wife found out that I and my daughter are not on the list".
The Organisation for Security and Co-operation in Europe (OSCE) sent more than 400 observers to monitor the polls.
Armaz Akhvlediyani - a member of parliament in the government bloc - said: "It's a quite normal and stable environment to manage democratic elections, so I have great hope regarding this event".