Georgia's interior minister was quoted as saying on Friday that the Russian troops had moved closer to his country’s borders.
Reports also said that the Russian Black Sea fleet is expected to start manoeuvres in the next few days.
Russia's Interfax news agency quoted the commander of the Russian military forces in Georgia as saying that the military might reconsider its plans to withdraw its troops from Georgia by 2008 because of the arrests of four Russian officers.
General Andrei Popov said that Russia's obligation to close its two remaining military bases in Georgia by the end of 2008 still stands, but added that "if our servicemen are arrested and put in custody, there will be problems with the withdrawal since there will be no people left to prepare weapons for the pullout", Interfax said.
Colonel Vladimir Kuparadze, Popov’s spokesman, said that the "current situation could significantly affect the process of withdrawing weapons, armament and other materials from Russian military bases".
Officers in custody
A court, meanwhile, has ordered two of the four officers arrested to remain in custody for another two months, an official said.
The detention of five Russian officers on Wednesday - one of them was released on Friday - plunged already tense relations between the two ex-Soviet neighbours to a new low, with Russia recalling its ambassador, evacuating some diplomats and their families and protesting to the UN.
Saakashvili accuses Moscow of
backing the separatists
Sergei Ivanov, the Russian defence minister, denounced Georgia as a "bandit" state.
The Tbilisi City Court ruled on Friday to keep two of the four remaining Russian officers in custody for another two months, and was set to consider the cases of the other two officers later in the day, Ilya Gergedava, the court spokesman, told The Associated Press.
Two Russian planes, meanwhile, evacuated 84 diplomats and their relatives from Georgia, officials said.
The espionage charges were officially filed on Friday against the Russian officers, who were detained on Wednesday, said Shota Khizanishvili, spokesman for Georgia's interior minister.
Bilateral ties long have been strained over Georgia's bid to join Nato and Moscow's close links to Georgia's breakaway provinces of Abkhazia and South Abkhazia.
Ivanov, meeting with Nato members in Slovenia, said Georgia's actions were "to push Russian peacekeepers out by any means possible ... and then to submit an application to join Nato".
"It is absolutely clear to us that Georgia has chosen the military path, the forceful path, for resolving the conflicts in South Ossetia and Abkhazia," he said.
"It is absolutely clear to us that Georgia has chosen the military path, the forceful path, for resolving the conflicts in South Ossetia and Abkhazia"
Russia's Defence Minister
Georgian police still surrounded the Russian military headquarters in Tbilisi on Friday, hoping to detain another Russian officer accused of spying.
Vyacheslav Kovalenko, the Russian ambassador, said that Moscow would not surrender the officer.
Meanwhile, in Moscow, police blocked off the streets around the Georgian embassy. Police allowed a group of some 20 activists to stage a brief protest against Georgia's president outside security cordons before detaining them for holding an unsanctioned rally.
Separately, an official in South Ossetia claimed that masked Georgian military or security officers shot out the tires of a car carrying four Russian peacekeepers, a woman and a child on Thursday night, then ordered the men out and beat them.
One peacekeeper sustained a fractured skull, according to the internationally unrecognised South Ossetian government, and Ivanov said there was proof they were "brutally beaten".
Georgian officials denied the allegations, saying police stopped a car with Russian peacekeepers, checked their documents and released them.
Russia's foreign ministry advised its citizens to refrain from traveling to Georgia, citing security concerns, and its embassy in Tbilisi stopped issuing visas to Georgian citizens.
Mikhail Saakashvili, Georgian president, denounced the moves as hysteria.
Relations between Moscow and Tbilisi have become increasingly tense since Saakashvili came to power following Georgia's 2003 Rose Revolution, pledging to move the country out of Russia's orbit.
Tbilisi officials have accused Russia of backing separatists in Georgia's breakaway provinces of Abkhazia and South Ossetia and making efforts to undermine Saakashvili's government - allegations Russia has denied.