Seven Russian soldiers were killed on Friday in an apparent car bomb attack in the Georgian separatist region of South Ossetia condemned by Moscow as an attempt to undermine the EU-Russia peace accord.
"The ministry of defence sees the accident as a terrorist attack aimed at undermining the application" of the peace agreement, said a Russian defence ministry statement.
The agreement was reached on September 8 when French President Nicolas Sarkozy, whose country holds the European Union presidency, and Russian President Dmitry Medvedev agreed a timetable for Russian forces to pull out of undisputed Georgian territory following the two countries' conflict over South Ossetia.
Under the plan, Russia is also due to draw back its troops from "buffer zones" around the rebel regions of South Ossetia and Abkhazia into the regions themselves by October 10.
Seven servicemen were killed and seven others wounded in the blast in the South Ossetian capital Tskhinvali where Russian troops are based, Major-General Marat Kulakhmetov told Interfax news agency in the city.
The wounded were evacuated by helicopter and taken to defence ministry hospitals in Russia, the report quoted him as saying.
Local officials in the rebel province said the Russian soldiers were killed after security forces seized from Georgian citizens a suspect automobile that turned out to be packed with explosives that blew up near their main base.
The leader of the rebel province, Eduard Kokoity, immediately blamed the attack on Georgia, an accusation Tbilisi promptly rejected.
"This was an attack planned by the Georgian Ministry of National Security," Kokoity told Russia's state-run ITAR-TASS news agency in Tskhinvali.
Georgian Interior Ministry spokesman Shota Utiashivili denied any Georgian involvement.
"I think this is a provocation with the aim of keeping Russian forces in Georgia," Utiashvili told AFP in Tbilisi.
The apparent attack marked the most serious violence in the region since the brief war that broke out in South Ossetia in August between Russia and Georgia.
It also occurred just three days after more than 200 European observers deployed in various parts of Georgia at the start of a major mission to monitor the ceasefire and oversee the pull-back of Russian troops.
The French EU presidency on Friday condemned the attack as well as the earlier killings of Georgian police officers, a reference to deadly sniper attacks last month on two police officers from separatist positions in Georgia's other separatist region of Abkhazia.
In a statement it said it condemned "the acts of violence which have taken place in recent days in Georgia, whether it be the murder of Georgian police officers or the bombing this afternoon (Friday) in Tskhinvali."
It added that it hoped that "light will be shed on these acts. All efforts must be made to preserve peace and security in the region."
Thousands of Russian troops remain deployed in South Ossetia and Abkhazia, and are also in "buffer zone" positions outside those provinces in undisputed Georgian territory.
Medvedev on Thursday reiterated that Russian forces would pull out of that undisputed territory no later than October 10 under the terms of the peace agreement.
South Ossetia declared its independence from Georgia after defeating Georgian forces in a war in 1992 in the immediate aftermath of the collapse of the Soviet Union the previous year.
The rebel province enjoyed de facto independence until August, when Georgian forces launched an attack in a bid to regain control of South Ossetia by force.
Russia responded by pouring forces into the province, officially in defence of the many residents who hold Russian citizenship, quickly routing Georgian troops and taking control of South Ossetia and Abkhazia.
Shortly afterwards, Russia formally recognised both rebel Georgian provinces as independent countries, a move fiercely opposed by Georgia and its allies in the West and so far followed by no other country except Nicaragua.
The Russian foreign ministry said Friday that the Swiss embassy would represent Russian interests in Georgia after Moscow closed its embassy in Tbilisi last month following the end of fighting.