Members of the unified opposition, led by their presidential candidate, Levan Gachechiladze, entered Tarkhnishvili's office to accuse him of electoral fraud and demanded his resignation.
With about 10 percent of the vote left to be counted, official figures show incumbent leader Mikheil Saakashvili winning the January 6 poll with about 52 percent of the vote, compared to about 25 percent for second-place finisher Gachechiladze.
In order to secure a first-round victory, Saakashvili needs 50 percent plus one vote -- a tally that appears to be within his grasp and which will allow him to avoid a runoff.
Gachechiladze's supporters, however, are claiming to have uncovered voting discrepancies, and announced during a press conference on January 7 that they intend to "fight for each and every vote."
During the confrontation at Tarkhnishvili's office on January 8, an agitated Gachechiladze had harsh words for the Central Election Commission chairman. "We are talking to you the way you are talking to the Georgian people," Gachechiladze said. "You are rigging the elections, and you are accountable for this before the entire Georgian nation. And you will be punished for this, I give you my word!"
Gachechiladze demanded that Tarkhnishvili provide vote-summary protocols -- which the opposition claims are being falsified -- to determine whether there are discrepancies with voting data released by the Central Election Commission.
Tarkhnishvili, in turn, accused the opposition politicians of trying to pressure him. "You have broken into my office," he told them. "This is not a normal working condition."
The opposition politicians had threatened earlier to launch protest rallies on January 8 in the capital, Tbilisi, to demand that the presidential election results be annulled. But the rally was called off at the last minute, with the opposition saying it would instead rely on the courts to rule on alleged cases of ballot fraud and manipulation of results.
Meanwhile, foreign observers continue to maintain that although there were some violations, the vote was mainly free and fair.
U.S. State Department spokesman Sean McCormack, speaking to reporters in Washington on January 7, underlined that the vote was conducted "largely" in accordance with international standards.
"We would like to congratulate the people of Georgia on an election that was conducted largely in accordance with international standards, as judged by the OSCE," McCormack said. "The head of mission on the ground there said they should be congratulated on that. That same mission did identify some problems, which we would urge the government of Georgia to address. But on the whole, in the assessment of that mission, it was a good election that reflected the will of the Georgian people."
Congratulations were also issued by the European Union, which issued a statement calling on all political forces in Georgia to respect the election results and engage "constructively and democratically in order to ensure that Georgia continues moving forward."
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