As Russian troops advanced towards the capital of Georgia's separatist region, Sergei Lavrov, Russia's foreign minister, said "ethnic cleansing" had been reported in villages in South Ossetia amid a Georgian offensive to retake the breakaway region.

Mr Lavrov called on the West to reach "the right conclusions" over the conflict, saying the Georgian offensive had been made possible by Western military aid to Tbilisi.

"Now we see Georgia has found a use for these weapons and for the special forces that were trained with the help of international instructors," he said.

"I think our European and American colleagues ... should understand what is happening. And I hope very much that they will reach the right conclusions."

The military operation marks the first time Russian troops have taken action on foreign soil since the Soviet withdrawal from Afghanistan in 1989.

Georgia has warned that any involvement of Russian forces in the conflict would result in a state of war between the two countries.

The Russian military reported that ten Russians were killed and 30 injured during Georgian shelling of their barracks, but Georgian officials denied firing on Russian peacekeepers in the area during their offensive in South Ossetia.

Georgian troops had earlier launched a massive attack to regain control of breakaway South Ossetia, where officials said at least 15 people were killed and an unspecified number of people wounded.

Georgia v Russia: By numbers

Georgia
Russia:

Population

4.6 million
140 million

Army

18,000
400,000

Tanks

128
23,000

Fighter jets

9
1,736

The move by Russian troops followed a series of statements by Russian leaders pledging to protect Russian citizens in the region in the face of a massive Georgian military attack on South Ossetia.

Mr Putin, on a trip to Beijing to attend the Olympics opening, sharply criticised the Georgian attack and warned it will draw retaliatory actions. He spoke after meeting briefly with US President George W Bush in Beijing.

Mr Putin did not specify what kind of retaliatory action may follow, but Russia's Defence Ministry pledged to protect Russian citizens in the region. Most of the region's residents have Russian passports.

Russian President Dmitry Medvedev later chaired a session of his security council in the Kremlin, vowing that Moscow will protect Russian citizens.

"In accordance with the constitution and the federal law, I, as president of Russia, am obliged to protect the lives and dignity of Russian citizens wherever they are located," Mr Medvedev said in televised remarks. "We won't allow the death of our compatriots to go unpunished."

Russia's Defence Ministry denounced the Georgian attack as a "dirty adventure."

"Blood shed in South Ossetia will weigh on their conscience," the ministry said in a statement posted on its official website.

"We will protect our peacekeepers and Russian citizens," it said without elaboration.

Georgian President Mikhail Saakashvili accused Russia of aggression, saying that Russian jets bombed several Georgian villages, wounding seven civilians. A Russian diplomat denied that Russian aircraft had bombed Georgian territory.