Georgia is marking the fifth anniversary of the so-called Rose Revolution which swept Mikhail Saakashvili to the presidency.
Amid concerns over the country's relationship with Russia, official celebrations on Sunday to mark the pro-Western revolution will be kept low-key, with a concert at Tbilisi's opera house being the cornerstone event.
A day earlier, Saakashvili appealed to Georgians to remain united against Russia, whose forces battled the Georgian army over the breakaway region of South Ossetia in August.
"We were attacked because of the success of the last five years, it was the last challenge of the empire against us," he said.
"We have never faced such a dangerous threat. We need strength and unity. We must believe in the future and have courage. Instead of celebrating tomorrow, we must show unity as we did on November 23, 2003."
But although Russia was widely criticised by the US and EU in its war on Georgia, Saakashvili is now facing increasing opposition at home.
Nino Burjanadze, a ex-ally of Saakashvili and former speaker of parliament, was set to found a new opposition political party on the anniversary.
Also on Sunday, up to 350 opposition supporters demonstrated outside the office of the Imedi television channel, which was closed down in November 2007 during a state of emergency imposed by Saakashvili.
Although Imedi is now back on air under new ownership, the opposition says that it takes an uncritical line on the government.
"We are demanding that Imedi be returned to its legal owners and that the opposition have live air time," Levan Gachechiladze, an opposition leader, said.
In November 2003, tens of thousands of people protested in the centre of Tbilisi, Georgia's capital, against parliamentary elections won by allies of Eduard Shevardnadze, who was then president.
Shevardnadze stood down as president after protesters stormed the parliament building.
'Crackdown on dissent'
After taking power, Saakashvili undertook a programme of political change that were well-received by Western governments, while pledging to win Georgia membership of the European Union and Nato.
But critics say that the president has resorted to harsh measures against the political opposition.
Last year, police used violence against tens of thousands of anti-government protesters and Saakashvili briefly imposed emergency law.
He has also been fiercely criticised for the government's strategy in Georgia-Russia war in August.