Thousands of protesters have tried to storm the parliament building in the Georgian capital of Tbilisi and are calling for the government's resignation.
The unrest was sparked by the appearance Thursday of Russian legislator Sergei Gavrilov in the building as part of an assembly of legislators from Orthodox Christian countries.
Gavrilov's support for independence for the Georgian breakaway regions of Abkhazia and South Ossetia and his support of Russian President Vladimir Putin has stoked animosity in Georgia.
Police turned back an attempt by the crowd to storm the building.
Earlier, tens of thousands rallied in central Tbilisi, demanding speaker Irakli Kobakhidze step down after Gavrilov addressed the country's parliament from the speaker's seat.
Russian Communist lawmaker Gavrilov was speaking during an annual meeting of the Inter-parliamentary Assembly on Orthodoxy (IAO), a forum of lawmakers from predominantly Orthodox countries.
The Russian lawmaker's presence in fiercely pro-Western Georgia's parliament prompted outrage in the ex-Soviet nation which in 2008 fought and lost a brief but bloody war with Moscow over the breakaway regions of Abkhazia and South Ossetia.
A group of Georgian opposition lawmakers demanded the Russian delegation leave the parliament's plenary chamber.
Many protesters held Georgian and EU flags and placards that read "Russia is an occupier."
"This is a spontaneous protest by ordinary Georgians, it has not been organized by any political party," a lawmaker from opposition European Georgia party, Giga Bokeria, told French Press Agency (AFP) at the rally.
Georgian oligarch Bidzina Ivanishvili — widely believed to be calling the shots in Georgia as the leader of his ruling Georgian Dream party — said in a statement he "fully shares the sincere outrage of the Georgian citizens."
"It is unacceptable that a representative of the occupier country chairs a forum in the Georgian parliament," Ivanishvili said.
He added he had told speaker Kobakhidze, to "immediately suspend" the IAO session.
Headquartered in Athens, the IAO is a permanent, international forum of MPs from predominantly Orthodox-Christian countries.
Georgia and its Soviet-era master Russia have long been at loggerheads over Tbilisi's bid to join the European Union and NATO with the spiraling confrontation culminating in a full-out war on August 8, 2008.
The Russian army swept into Georgia — bombing targets and occupying large swathes of territory — after Tbilisi launched a large-scale military operation against South Ossetian separatist forces who had been shelling Georgian villages.
Over just five days, Russia defeated Georgia's small military and the hostilities ended with a ceasefire mediated by France's then-president Nicolas Sarkozy, who at the time held the EU's rotating presidency.
After the war, which claimed the lives of hundreds of soldiers and civilians from both sides, Moscow recognized South Ossetia and Abkhazia as independent states where it then stationed permanent military bases.
Tbilisi and its Western allies have denounced the move as an "illegal military occupation."
The two regions constitute 20 percent of the country's territory.
