Georgia's ruling party on Saturday installed a far-right former footballer as president in a controversial election process, amid a deepening constitutional crisis and weeks of mass pro-EU protests.
The Black Sea nation has been in turmoil since the governing Georgian Dream party claimed victory in contested October parliamentary elections.
Its decision last month to delay European Union membership talks ignited a fresh wave of mass rallies.
An electoral college, controlled by the ruling Georgian Dream party and boycotted by the opposition, elected Mikheil Kavelashvili with a comfortable majority of 224 votes as the country's next figurehead leader for a five-year term, the central election commission said.
Kavelashvili is a 53-year-old former forward for English Premier League champions Manchester City. An MP since 2016, he is known for airing far-right views in obscenity-laced statements.
"Over the years, certain forces -- particularly external ones -- have exploited the presidential institution to divide society," Prime Minister Irakli Kobakhidze, told journalists.
"Under Mikheil Kavelashvili's presidency, it will regain its constitutional mission and dignity."
The opposition has denounced Saturday's election as "illegitimate" and said the sitting president, Salome Zurabishvili, remains the country's sole legitimate leader.
Pro-Western Zurabishvili -- at loggerheads with Georgian Dream -- has refused to step down and is demanding new parliamentary elections, paving the way for a constitutional showdown.
"Georgia never loses its sense of humor, celebrating the election of a footballer as president," Zurabishvili wrote on social media, saying the vote made "a mockery of democracy".
A former diplomat, Zurabishvili is a hugely popular figure among protesters, who view her as a beacon of Georgia's European aspirations.
On Saturday protesters began gathering outside the parliament building -- which was cordoned off by police -- ahead of a planned opposition rally in the evening.
Some demonstrators shared tea to keep warm on a frosty day with water cannons parked nearby, an AFP reporter witnessed.
One protester, 40-year-old Natia Apkhazava, said she wanted "to protect our European future".
"Our (parliamentary) election was rigged. We need new elections," she said.
"We have been protesting here for 16 days and we'll keep fighting for our European future."
Thousands of pro-EU demonstrators on Friday gathered outside parliament for the 16th consecutive night of protests.
'Unprecedented constitutional crisis'
Opposition groups accuse Georgian Dream of rigging the October 26 parliamentary vote, backsliding on democracy and moving Tbilisi closer to Russia -- despite the Caucasus nation's constitutionally mandated bid to join the European Union.
Kavelashvili -- the sole candidate for the largely ceremonial presidential post -- is known for vehemently anti-Western diatribes and opposition to LGBTQ rights.
Georgian Dream scrapped direct presidential elections in 2017.
With Zurabishvili refusing to leave office, opposition lawmakers boycotting parliament, and protests showing no signs of abating, the legitimacy of Kavelashvili's election has been undermined from the outset.
Georgia's leading election watchdog, the International Society for Fair Elections and Democracy, said: "Any decisions made by this illegitimate parliament, including the scheduling and holding of the presidential election, are unconstitutional and unlawful."
One author of Georgia's constitution, Vakhtang Khmaladze, has argued that all decisions by the new parliament are void.
"Georgia is facing an unprecedented constitutional crisis," Khmaladze told AFP.
It remains unclear how the government will react if Zurabishvili refuses to step down after her successor is inaugurated on December 29.
Western hesitation
Police have fired tear gas and water cannons during more than two weeks of demonstrations and arrested over 400 protesters, according to the Social Justice Centre, an NGO.
On Friday, Amnesty International said protesters had faced "brutal dispersal tactics, arbitrary detention, and torture".
There have also been raids on the offices of opposition parties and arrests of their leaders.
As international condemnation of the police crackdown mounted, French President Emmanuel Macron told Georgians their "European dream must not be extinguished".
Earlier this week, Macron made a phone call to Georgian Dream founder Bidzina Ivanishvili -- the tycoon widely considered to be Georgia's real power broker.
His decision to call Ivanishvili -- rather than Prime Minister Irakli Kobakhidze -- was indicative of the West's hesitancy to recognise the legitimacy of Georgia's new government.
Washington has imposed fresh sanctions on Georgian officials, barring around 20 people accused of "undermining democracy in Georgia", including ministers and parliamentarians.