A sea of demonstrators waving Georgian flags packed into the main square in front of the east European country's parliament. Opposition leaders were insisting, among other demands, that Saakashvili bring forward to spring 2008 parliamentary elections set for late next year.

The protesters were told a delegation of seven opposition leaders met Friday with the speaker of Georgia's parliament, Nino Burjanadze, to discuss the demands.

"We are not going to disperse unless we receive an acceptable response from the authorities," said Gia Tortladze of the Movement for United Georgia.

But after the talks, Burjanadze told the Georgian television network, Imedi, that parliamentary elections would go ahead as originally planned.

She added, however, that the government is still in discussions with the opposition over other issues, which include calls for changes to the electoral system and for the release of "political prisoners" and "prisoners of conscience."

The latter is thought to be a reference to the former defense minister, Irakli Okruashvili, who was arrested but then freed on multimillion-dollar bail last month after he retracted allegations accusing Saakashvili of corruption and a murder plot.

The president of Georgia called the allegations "unpardonable lies."

Opposition leaders claimed around 150,000 people attended the protest, but European media reports put the figure at an estimated 40,000.

Even so, the protests are the biggest in the east European country since a peaceful revolution drove then President Eduard Shevardnadze from power in 2003.

Shevardnadze was replaced by Saakashvili, who was swept to power on a promise to tackle corruption in the former Soviet satellite state. However, the country is still struggling to recover from years of post-Soviet economic decay, instability and civil war.

Demonstrators accuse the Georgian leader of political persecution, abuse of the judicial process, and failing to tackle high levels of unemployment. They claim he has spent too much time trying to improve his international profile, including a bid for Georgia to join NATO.

Demonstrators at the rally told CNN it was being conducted in a "peaceful and cheerful" atmosphere. A 40-year-old protester told CNN by phone that he had taken the day off work to attend the protest and vowed to stay there until the president agreed to meet opposition demands.