Georgian Prime Minister Irakli Kobakhidze on Sunday accused opposition protesters of attempting to overthrow his government and vowed to clamp down on any dissent.

Saturday saw tens of thousands of anti-government protesters take to the streets of the capital, Tbilisi, many waving Georgian and EU flags.

Riot police used water cannons and tear gas to stop them from forcing their way into the presidential palace.

Kobakhidze's Georgian Dream party on Saturday claimed victory in every municipality across the country in local elections boycotted by the two main opposition blocs.

'No one will go unpunished,' warns Kobakhidze

"Several people have already been arrested — first and foremost the organisers of the attempted overthrow," Kobakhidze told journalists.

"No one will go unpunished... many more must expect sentences for the violence they carried out against the state and law enforcement," he added.

Among those arrested was world-renowned opera singer and activist Paata Burchuladze. At the rally, he read out a declaration claiming "power returns to the people" and branded the government "illegitimate."

On Sunday evening, Georgia's State Security Service (SSS) said a cache of firearms, ammunition and explosives had been discovered in a forest hideout near the capital.

Georgian state security said the items were intended for "subversive acts" on election day in concert with organised street violence and an attempt to seize the presidential palace.

According to the prime minister, up to 7,000 people attended Saturday's rally, but their "attempt to overthrow the constitutional order" had failed despite what he alleged was support from Brussels.

He accused EU Ambassador Pawel Herczynski of interfering in Georgian politics and called on him to condemn the protests.

"You know that specific people from abroad have even expressed direct support for all this, for the announced attempt to overthrow the constitutional order," Interpress cited Kobakhidze as saying.

EU rejects 'disinformation' and calls for calm

EU foreign policy chief Kaja Kallas issued a statement in which she said the EU "firmly rejects and condemns the disinformation regarding the EU's role in Georgia and denounces the personal attacks against the ambassador of the European Union to Georgia."

"Months of raids on independent media, the passing of laws targeting civil society, the jailing of opponents and activists or amendments to the electoral code favouring the ruling party, drastically reduced the possibility of having competitive elections," the EU statement said. 

In the statement, Kallas went on to call for restraint on the part of Georgian authorities.

"We urge calm and restraint in the post-election period and call on the authorities to uphold citizens' rights to freedom of assembly and expression," the EU statement said.

Edited by: Sean Sinico