Foreign secretary David Miliband has said that Russia has a "responsibility" not to start a new Cold War after flying to neighbouring Ukraine.
|A shell casing lies inside a destroyed building in South Ossetia|
He was speaking in Kiev following Russia's decision to formally recognise two breakaway regions of Georgia.
Georgia has recalled all but two of its diplomats from Moscow in protest, while Nato has urged the Kremlin to reverse its decision.
Russian president Dmitry Medvedev has been accused of "inflaming" the crisis by insisting that South Ossetia and Abkhazia should be independent.
He also warned that he could authorise military force to respond to the controversial deployment of an American missile defence shield in Poland and the Czech Republic.
Mr Miliband said: "Russia has not reconciled itself to the new map of this new region.
"We do not want a new Cold War and he (Mr Medvedev) has a big responsibility not to start one."
He added that the West must not seek to isolate Russia.
"Isolation is not feasible. Russia is too enmeshed in the world economy. It would be counterproductive," he said.
Mr Miliband's comments came as a US military ship carrying 34 tons of humanitarian aid docked at the Georgian port of Batumi.
But in response, the Russians to send three of its military ships to another Georgian port.