Russian troops have entered Georgia from the breakaway region of Abkhazia,
as the conflict between the two neighbours appears to be broadening.
Moscow said it had launched a raid on the town of Senaki to stop Georgia from attacking Russian forces in South Ossetia, another breakaway region.
As the fighting continued in South Ossetia, foreign envoys were pressing for a ceasefire in the conflict.
Each side accuses the other of carrying out atrocities in the region.
Fighting in South Ossetia erupted late last week when Georgia launched an overnight assault on the territory.
Russia, which supports the province's bid for separation, then bombed targets throughout Georgia and moved troops into the region and into Abkhazia.
On Monday EU envoys were attempting to broker an agreement between Tbilisi and Moscow.
Georgian President Mikhail Saakashvili signed an EU-backed ceasefire, but the document was rejected by Moscow.
And leaders from both countries carried on a war of words, with Russia accusing Georgia of genocide, and President Saakashvili hitting back with claims of ethnic cleansing.