Both sides are claiming victory in Georgia's parliamentary election, even with the outcome far from certain.

Pro-Russian billionaire businessman Bidzina Ivanishvili's Georgian Dream coalition is challenging President Mikhail Saakashvili's United National Movement for control of parliament.

Exit polls give Georgia Dream the lead, based on the count of votes for party lists. This accounts for about half the seats.

Mr. Saakashvili says his party has won where the seats are filled by popular vote for individual candidates.

Despite the mixed results so far, thousands of opposition supporters celebrated in central Tbilisi Monday night.

Under the new Georgian constitution, the prime minister will assume many of the powers now held by the president when Mr. Saakashvili's second and last term ends next year. Parliament will choose the new prime minister.

President Saakashvili has said a victory for Georgian Dream and Ivanishvili as prime minister would move Georgia away from the West and put it back under Moscow's influence. Ivanishvili denies this.

His backers accuse the president of being a dictator. They blame him for the brief but disastrous 2008 war with Russia over the breakaway region of South Ossetia. Mr. Saakashvili's campaign also was hurt last week when videos surfaced of prison guards beating and raping inmates.

Amnesty International is condemning what it says were human rights abuses during the election campaign. The group Monday said Georgian Dream supporters were arrested, harassed, fined or fired from their jobs for expressing their political views.

Georgian officials have not yet responded to the Amnesty report.