Georgian antigovernment protesters have clashed with police, attacking a law-enforcement vehicle and prompting police to fire rubber bullets and use tear gas.
The incident comes a day after thousands of opposition protesters took to the streets to call for the resignation of President Mikheil Saakashvili in one of the largest antigovernment demonstrations seen in Georgia since 2009.
Opposition leaders say they attacked the car because police tried to arrest one of the protest leaders.
Opposition leader Nino Burjanadze described the incident to RFE/RL's Georgian Service.
"We were just protecting ourselves. We did not start the violence, the Georgian government did. We were only protecting ourselves, which is a right provided to us by the constitution, as it is in most constitutions," Burjanadze said.
"People will be referencing this right in their demonstrations. We will seize this neo-Bolshevik regime. We'll win back our right to a free and democratic election and be done with this government."
Interior Ministry spokesman Shota Utiashvili said the police response was not intended to disperse the rally and was only meant to curb aggressive protesters.
Opposition leaders say dozens of activists have been arrested in the unrest over the last several days, and have called for renewed full-scale protests later on May 22.
Saakashvili's term in office expires in 2013.