TBILISI - At least 60,000 Georgians rallied on Thursday at the start of a campaign to try to force President Mikheil Saakashvili to resign, an effort led by opponents emboldened by last year's disastrous war with Russia.

Opposition leaders have promised to demonstrate daily outside parliament in Tbilisi until Saakashvili quits, accusing him of monopolizing power and stifling reforms promised in the 2003 Rose Revolution that swept him to power.

War in August, when Russia crushed a Georgian assault on the breakaway South Ossetia region and sent tanks to within 40 km (25 miles) of Tbilisi, was seized on by critics who say the president has made too many mistakes to stay in power until 2013.

Saakashvili has polarized opinion in the former Soviet republic. But analysts say they doubt the opposition's strength of leadership, unity or support outside the capital are sufficient to force him out.

We have no other way out but to stand here until the end, until the Judas of Georgian politics resigns, former presidential challenger Levan Gachechiladze told the crowd.

Speakers complained of government pressure on the media and judiciary, and criticized last year's lost war. Protesters raised hands to endorse a statement urging Saakashvili to stand down. Organizers gave him 24 hours to reply, before announcing further action.

Today is referendum day in Georgia, said former U.N. ambassador Irakly Alasania, one of several senior figures to defect from Saakashvili citing serious errors of judgment.

But diplomats say Saakashvili's position remains strong despite the war, the defections and repeated cabinet reshuffles that have fueled questions over his leadership style.

Many Georgians are tired of political bickering in the capital and are sympathetic to government calls for stability as a global economic crisis deepens.

OPPOSITION ALLEGES FOUL PLAY

Perceived as brash and impulsive, Saakashvili's handling of the war has come under some scrutiny among Georgians. But he draws support from the prevailing consensus in the country that Russia was to blame.

The West, which imports oil and gas via Georgia from the Caspian Sea, is watching for a possible repeat of a November 2007 crackdown, when police firing teargas and rubber bullets dispersed the last major demonstrations against Saakashvili.

Police denied allegations they had detained around 60 opposition activists overnight in the town of Rustavi southeast of Tbilisi. The opposition also accused the authorities of limiting public transport from western Georgia to Tbilisi.

Opposition leaders said there were at least 150,000 people in the streets. The government sent mobile phone text messages to journalists saying there were only 25,000.

I have not seen such unity among Georgians for a long time, said protester Elene Gabriadze, a 47-year-old unemployed woman. We will stand here until the end.

Fire crews and hundreds of police in riot gear lounged on the stone floor of the parliament courtyard.

Saakashvili's mainly Western-educated team came to power blessed by former U.S. president George W. Bush as a beacon of liberty. But the light has faded and diplomats say Barack Obama's administration will be less forgiving of any crackdown.

Thursday's rally was timed to coincide with the 20th anniversary of Soviet troops' bloody crushing of pro-independence Georgian protests, two years before the Soviet Union collapsed.

Before the demonstration, Saakashvili joined hundreds of people in front of parliament in a quiet vigil to remember the victims. Georgia today, as never before, needs unity and firmness, he told reporters. We are a democratic state and people have different opinions.

Fear of unrest has been fed by the authorities, who in March said they had uncovered a plot to overthrow the government by men with suspected links to the opposition. The opposition accused the authorities of conducting a smear campaign.

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