Georgia's President Mikhail Saakashvili has accused "Russian special services" of stirring up the civil unrest in the capital, Tbilisi.
Mr Saakashvili was speaking after riot police used tear gas and water cannon to disperse opposition demonstrators staging a sixth day of protests.
The health minister said 250 people had been admitted to hospital.
Mr Saakashvili has rejected the protesters' accusations of corruption and says he will not quit.
In a televised address, Mr Saakashvili said his country faced "a very serious threat of unrest".
"High ranking officials in Russian special services are behind this," he said, adding that he had evidence.
He said several Russian diplomats would be expelled from Georgia for engaging in "espionage".
Earlier he had recalled Georgia's ambassador to Moscow for "consultations".
Police used tear gas and water cannon after several thousand protesters tried to occupy Rustaveli Avenue - Tbilisi's main thoroughfare.
The BBC's Matthew Collin in Tbilisi says the police action provoked chaos among the demonstrators, sending them running for cover.
The protesters had been regrouping after police forced them off the city's main street in front of parliament.
The protesters say the police response demonstrates Mr Saakashvili's authoritarian tendencies.
The opposition said police had arrested two of its leaders and beaten several of its supporters during an earlier raid.
The authorities said they had to act to unblock the city's main thoroughfare and stop protesters from setting up a tent camp there. A government official said the rally could continue on the pavement.
Opposition supporters have been gathering outside parliament every day since Friday, when 50,000 people attended the largest street protest seen since the 2003 "Rose Revolution" that brought pro-Western Mr Saakashvili to power.
Mr Saakashvili has rejected the allegations against him
The protesters accuse him of corruption and of not doing enough to tackle poverty.
They are calling for the president's resignation and want a fresh election.
Many of the protesters back the president's former ally, Irakli Okruashvili, who was arrested last month.
Mr Okruashvili was detained shortly after he said Mr Saakashvili had plotted to kill a top businessman. He was later released on a multimillion-dollar bail and went to Germany.
The government says Mr Okruashvili's accusations are "false and baseless".
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