Georgia’s Central Election Commission reported that the ruling Georgian Dream party won 52.99 percent of the vote with just over two-thirds of the votes counted.
Not all paper ballots and votes cast by Georgians abroad were counted.
Bidzina Ivanishvili, the founder of Georgian Dream, announced the victory almost immediately after the polls closed and said: “It is rare in the world for the same party to achieve such success in such a difficult situation.”
Earlier on Saturday, opposition parties claimed victory when competing exit polls were published.
If Georgian Dream’s victory is confirmed, it will have a parliamentary majority, stoking fears about the country’s bid for EU membership.
Brussels has halted Georgia’s membership process after Georgian Dream passed laws undermining freedom of speech.
Many Georgians saw the vote as a referendum on whether to join the European Union.
The election campaign in the South Caucasus nation of 3.7 million people, which borders Russia, was dominated by foreign policy and marked by a fierce battle for votes and accusations of a smear campaign.
The outcome will determine whether Georgia gets back on the path to EU membership or embraces authoritarianism and falls into Russia’s orbit.
Some Georgians complained of intimidation and pressure to vote for Georgian Dream, while the opposition accused the party of waging a “hybrid war” against its citizens.
The largest opposition party, the United National Movement, said its headquarters were attacked on election day.
Georgian media also reported that two people were taken to hospital after being attacked outside polling stations, one in the town of Zugdidi and the other in Marneuli, a town south of the capital Tbilisi.
There were also reports of irregularities in the voting.
A video shared on social media on Saturday also shows a man stuffing ballot papers into a box at a polling station in Marneuli.
Georgia’s Ministry of Internal Affairs said it had launched an investigation, and the Central Election Commission said a criminal case had been opened and that all polling station results would be declared invalid.
Ahead of the parliamentary elections, Bidzina Ivanishvili – a shadowy billionaire who created Georgian Dream and amassed his fortune in Russia – again vowed to ban opposition parties if his party won.
Georgian Dream will hold opposition parties “fully accountable with the full force of the law” for “war crimes” committed against the people of Georgia, Ivanishvili told a pro-government rally in Tbilisi on Wednesday.
He did not explain what crimes he believed the opposition had committed.
Many believed the election was the most important vote since Georgia gained independence after the collapse of the Soviet Union in 1991.
Georgian President Salome Zurabishvili described them as “existential elections”.
Georgians want “European integration, they want to move forward and they want policies that will bring us a better, more stable future,” Christine Tordia, 29, told The Associated Press (AP) shortly after the vote in Tbilisi.
About 80 percent of Georgians support joining the EU, according to polls, and the country’s constitution obliges its leaders to seek membership in the bloc and NATO.
But Brussels has put Georgia’s bid to join the EU on hold indefinitely after the ruling party passed a “Russian law” curtailing freedom of speech in June.
Many Georgians fear the party is pushing the country toward authoritarianism and killing hopes it could join the EU.
The election “is not just about changing the government, but whether Georgia will survive or not, because Ivanishvili’s government means Russia,” said Nika Gvaramiya, leader of the Coalition for Change, an opposition group.
Mr Ivanishvili voted on Saturday morning amid heightened security.
He did not respond to an AP question about whether he wants to form an alliance with Russia.
He said the election was a choice between “a government that will serve you” or “choosing agents of a foreign country who will only do the foreign country’s bidding.”
Mr Ivanishvili did not specify which country he was referring to, but before the election he and his officials claimed that a “party of global war” sought to influence the EU and the US, expand the conflict in Ukraine and force Georgian Dream to cede power.
In the vote, Georgians will elect 150 legislators from 18 parties.
If no party wins the 76 seats needed to form a government for a four-year term, the president will invite the largest party to form a coalition.
Opposition parties ignored Ms Zurabishvili’s demand to unite into one party, but signed her “charter” to carry out the reforms required by the EU to join.
Georgian Dream put up billboards across the country contrasting black-and-white images of the destruction in Ukraine with colorful images of life in Georgia along with the slogan “Say no to war – choose peace.”
The ruling and opposition parties have told voters they will pursue EU membership, although laws passed by Georgian Dream have put that hope on hold.
At last week’s EU summit, EU leaders said they had “serious concerns about the course of action taken by the Georgian government”.
Georgian Dream faced three coalitions: National Unity Movement, Coalition for Change and Strong Georgia.
The Gakharia Party for Georgia, founded by former Prime Minister Giorgi Gakharia, has said it will not enter into an alliance with anyone but will support the opposition to form a government.