Saturday's election was the first real test for the ruling Georgian Dream since the disputed election last year, which led to the EU pausing the country's candidacy.
When 75 percent of the electoral districts had reported their figures, the election authority announced that Georgian Dream had gained a majority in all of the country's municipalities, with more than 80 percent of the votes.
In addition, they have secured the post of mayor in all cities.
Marched towards the palace
Tens of thousands of demonstrators gathered on Freedom Square in Tbilisi to protest against the result, waving Georgian and EU flags.
The former opera singer Paata Burchuladze held a acclaimed speech where he declared the government illegal and that power should return to the people.
The demonstrators then marched towards the presidential palace, where they tried to get in, after which the police fired both tear gas and water cannons.
Just before midnight, the situation had calmed down.
Prime Minister Irakli Kobakhidze says it was a "coup, planned by foreign intelligence services".
Every single person involved in this violent act will be prosecuted, he says at a press conference.
Russia-friendly government
The Ministry of Internal Affairs has launched an investigation into what it calls "calls for violent change of Georgia's constitutional order or to overthrow the state's authority".
Five leading figures in the demonstration movement have been arrested and risk up to five years in prison. Burchuladze is one of them, but was treated at a hospital during the night for a heart attack.
The local elections in the country are usually not as politically charged as this. But after months of protests against Georgian Dream, the imprisoned ex-president Micheil Saakasjvili urged, before the election, to protests in what he calls a "last chance" to save democracy in the country.
Georgian Dream has been accused in recent years of increasingly acting as a puppet of Russia. The party has, among other things, frozen the negotiations on accession to the EU and recently talked about completely banning the political opposition.
