Clashes erupted for a third night outside parliament in Georgia's capital Tbilisi as thousands continued to protest against the end of accession talks to join the EU.

Riot police responded to breaking windows and building barricades by firing water cannon and tear gas into the crowds. Local media reported other protests in towns and cities across Georgia.

The country was thrown into crisis on Thursday when the prime minister of the Georgian Dream party, Irakli Kobakhidze, said it was halting EU discussions for the next four years over what it called "blackmail" by the bloc. 

EU membership is overwhelmingly popular in Georgia, which has the aim of joining the bloc enshrined in its constitution. 

But its political direction has changed after the increasingly anti-Western ruling party was re-elected last month.

On Saturday, Kobakhidze accused the pro-EU opposition of plotting a revolution with the State Security Service saying political parties were attempting to "overthrow the government by force."

President Salome Zourabichvili, who opposes the government and supports EU membership but whose powers are mainly ceremonial, said she would not leave office when her term ends in December.

"There is no legitimate parliament and, therefore, an illegitimate parliament cannot elect a new president," she said. "Thus, no inauguration can take place, and my mandate continues until a legitimately elected parliament is formed."

Kobakhidze hit back on Sunday, saying the President would have to step down at the end of her term this month.

Kobakhidze also dismissed the United States' decision to suspend its strategic partnership with Georgia as a "temporary event", saying Georgia would talk to the new administration of President-elect Donald Trump when it takes office in January.

Georgian Dream won almost 54 percent of the vote in the October 26 election, defeating an opposition that says the vote was rigged. Both the ruling party and Georgia's electoral commission say the election was free and fair. Western countries have called for an investigation.

The ruling party campaigned on keeping the country at peace, and accuses the opposition of trying to draw Georgia into war with Russia on behalf of the West.

Over 200 serving diplomats signed an open letter condemning the government's stance. Hundreds of employees at Georgia's defense, justice and education ministries, and at the central bank, have also signed open letters condemning the decision to freeze EU accession talks.

There have been over 100 arrests in the last two days. The interior ministry said the actions "of some individuals" were violent and that police would "respond appropriately and in accordance with the law to every violation." 

The EU's new foreign policy chief Kaja Kallas on Sunday warned Georgian authorities over violence against demonstrators.

"It is clear that using violence against peaceful protesters is not acceptable, and the Georgian government should respect the will of the Georgian people," Kallas said. "When it comes to EU, then this clearly has consequences on our relationship with Georgia."

Kallas, who took office on Sunday with a visit to Ukraine, said "options" had been put forward to the EU's 27 member states on how to respond, including potentially imposing sanctions. "We have different options. But of course, we need to come to agreement."