Georgia opposition parties on Tuesday vowed "permanent protests" in a rare show of unity against the country's ruling party after police arrested protesters and used water cannon to disperse an anti-government rally.
Opposition supporters have staged a series of rallies in the capital Tbilisi over the last two weeks after the ruling Georgia Dream party voted down legislation to hold parliamentary elections next year under a new proportional voting system.
Up to 20,000 people took to the streets on Monday, urging the government to resign and calling for fresh parliamentary polls.
Braving sub-zero temperatures, hundreds of protesters stayed outside parliament overnight, blocking all four entrances and threatening to prevent lawmakers from entering the building.
On Tuesday morning, riot police used water cannon to disperse the crowd.
The interior ministry said in a statement that 28 protesters were arrested and several injured.
Opposition leaders said the use of police force would only galvanise protest movement and vowed to hold "permanent protests" until their demands are met.
On Tuesday evening hundreds of protesters gathered again outside parliament building while the leaders of opposition parties held talks on their future strategies.
- United front -
"All of Georgia's opposition parties have set up a consultative council and agreed that the ongoing protest movement will be permanent and continue until our goal of Georgia's de-oligarchisation is achieved," the leader of Georgia's Labour Party, Shalva Natelashvili, told journalists.
Giga Bokeria, the leader of the opposition European Georgia party, said a plenary session in parliament that has been scheduled for Wednesday has been cancelled as a result of ongoing protests.
"We will resume the blockade of parliament building when it attempts to convene," he told AFP, adding that the fresh "big protest rally" will be held next week.
The latest demonstrations began on November 14 when Georgian Dream MPs voted down the bill for parliamentary elections next year.
Opposition parties formed a rare united front to call for against Georgian Dream, which is led by oligarch Bidzina Ivanishvili.
The 63-year-old Ivanishvili -- who is widely believed to be calling the shots in Georgia -- is accused by critics of orchestrating the bill's failure.
Protesters say the current voting system unfairly favours the ruling party.
Georgian Dream won nearly 77 percent of seats in the 2016 parliamentary election despite garnering only 48.7 percent of the vote.
- Rejected compromise -
Georgian Dream has ruled out early polls.
On Monday, it also rejected the opposition's compromise proposal of legislative amendments that would create a level playing field for all political parties in the tiny Black Sea nation.
Last week, riot police also used water cannon to disperse protesters, arresting several dozen people outside parliament.
The embassies of the United States and European Union have criticised Georgian Dream's failure to introduce the electoral reform and expressed solidarity with the protesters.
Ivanishvili had promised "large-scale political reform" following a summer of protests that saw 240 people injured in a police crackdown.
Two protesters including a teenage girl lost an eye during those protests.
In power since 2012, the ruling party has seen its popularity plummet amid widespread discontent over economic stagnation and perceived backsliding on its commitment to democracy.
Critics accuse Ivanishvili of persecuting political opponents, suffocating critical media, and creating a corrupt political system where his private interests dominate government decision-making.