Georgian opposition parties have criticized President Mikheil Saakashvili's handling of the 2008 military conflict with Russia and have called for his resignation.
A joint declaration issued Thursday said, in its words, "the only possible way to save" Georgia is for Mr. Saakashvili to step down. The document also called for early elections, along with new electoral legislation. The main opposition group in parliament, the Christian Democrats, did not sign the declaration.
Presidential and parliamentary elections are slated in Georgia for 2013, and Mr. Saakashvili has ruled out early polls.
Russian forces invaded Georgia in August, as Georgian troops attempted to regain control of the pro-Russian breakaway region of South Ossetia. Russia later recognized the territory, and a second breakaway region, Abkhazia, as separate countries, over strong protests from Georgia and Western governments.
Mr. Saakashvili said he sent troops into South Ossetia in response to a Russian invasion.
Thousands of ethnic Georgian villagers with homes in the breakaway territories remain displaced following the conflict. Some of them fled the fighting and are afraid to return home. Many others saw their homes razed.
Some information for this report was provided by AFP and Reuters.