Riot police used water cannons on anti-government protesters outside Georgia's parliament building in the capital, Tbilisi, the BBC reports.

Thousands of people demonstrated on Monday evening calling for reform to the country's electoral system.

Several activists and a politician were arrested early on Tuesday, opposition leader Giorgi Vashadze said.

Rallies have been held for the last two weeks, with activists demanding proportional representation.

Georgia was due to switch to the proportional representation electoral system in 2024, but the opposition is calling for the date to be brought forward.

Campaigners say the current system favours the ruling Georgian Dream party, which has been in power since 2012.

Protesters blocked several entrances to parliament, in order to stop politicians being able to enter for a session on Tuesday.

A few hours before police forcefully dispersed the demonstration, Mamuka Mdinaradze, a ruling-party politician, told reporters: "If protesters violate the law, the state will act adequately."

Officers also used water cannons on protesters at a rally outside parliament last Monday, and arrested 37 people.