Russia's military may reconsider its plans to withdraw its troops from Georgia by 2008 because of the arrests of four Russian officers, Interfax news agency quoted the commander of Russian military forces in Georgia as saying.
A court, meanwhile, ordered two of the four officers to remain in custody for another two months, an official said.
Gen. 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.
Popov's spokesman, Col. Vladimir Kuparadze, told The Associated Press that the "current situation could significantly affect the process of withdrawing weapons, armament and other materials from Russian military bases."
The detention of five Russian officers on Wednesday - one of them was released Friday - plunged already tense relations between the two ex-Soviet neighbors to a new low, with Russia recalling its ambassador, evacuating some diplomats and their families and protesting to the United Nations. Russian Defense Minister Sergei Ivanov has denounced Georgia as a "bandit" state.
The Tbilisi City Court ruled 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, court spokesman Ilya Gergedava told The Associated Press.
Ivanov said Friday the arrests were aimed at pushing Russian troops from Georgia so the government could seize control of pro-Russian breakaway provinces by force, and he accused newer NATO members of illegally supplying Georgia with Soviet-made weapons.
Two Russian planes, meanwhile, evacuated 84 diplomats and their relatives from Georgia, officials said.
The espionage charges were officially filed Friday against the Russian officers, who were detained 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.
Georgian police still surrounded the Russian military headquarters in Tbilisi Friday, hoping to detain another Russian officer accused of spying. Russian Ambassador Vyacheslav Kovalenko said Moscow would not surrender the officer.
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 Thursday night, then ordered the men out and beat them.
One peacekeeper sustained a fractured skull, according to the internationally unrecognized 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.
Georgian President Mikhail Saakashvili 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.
NATO Secretary General Jaap de Hoop Scheffer called for "moderation and de-escalation, and that goes for both parties."
A U.S. State Department official said both sides had to work together to solve the situation.
Matthew J. Bryza, in Berlin for diplomatic consultations on Abkhazia, also told journalists that "Georgia has expressed its sovereign view ... that it doesn't want Russian peacekeepers on its territory. There is a question of what is prudent, and what is the most effective way of asserting that right in the case of Tbilisi."