Georgia has weakened its case for NATO membership as a result of its “irresponsible” decision to try and recover South Ossetia, a leading UK-based think-tank said on Thursday, warning that US attempts to bring the Georgians into the alliance risked dividing the west.

In its annual analysis of world events, the International Institute for Strategic Studies said Russia’s reaction to the Georgian move was “disproportionately strong” and “unjustified.” But the IISS warned that the west must be careful how it responded to Russia’s defiant mood, and avoid advancing its interests without being aware of the emotional response that this could elicit from the Russian leadership.