Georgia pulled its troops out of the capital of South Ossetia this morning as 10,000 more Russian troops entered Georgia.

Georgia's Reintegration Minister Temur Yakobashvili said the Georgian troops left Tskhinvali to provide a humanitarian corridor to evacuate those wounded from the capital. However, he said, Georgian troops remained in South Ossetia.

Shortly afterwards, a Georgian government statement said that the Russian troops had entered Georgia in two places.

Hours earlier, Russian warplanes pounded a military airfield near Georgia's capital, Tbilisi. Georgian officials said that Russian warplanes had bombed a military airfield close to Tbilisi's international airport and just eight miles from the capital, hours after launching raids on other parts of the republic beyond the conflict zone in the separatist region of South Ossetia. Russia was accused of seeking the "annihilation of its former Soviet satellite".

There were also signs that Russia was preparing to open up a second front from Georgia's other breakaway region of Abkhazia on the Black Sea coast. Georgia accused Moscow of sending troops by sea to Abkhazia and a United Nations peacekeeping official warned that separatist fighters were preparing an imminent attack on Georgia.

Eastern European countries that formerly belonged to the Soviet bloc called on Nato to oppose Russia's "imperialist" policy towards Georgia. The leaders of Estonia, Latvia, Lithuania and Poland denounced Moscow's "aggression" and called on the European Union and Nato to "stand up" to Russia, which itself accused neighbouring Ukraine of arming and "encouraging" Georgia to attack South Ossetia.

Sweden's Foreign Minister Carl Bildt also demanded a "very strong response" from the EU, and raised comparisons between Russian actions and those of Nazi Germany. He said: "No state has the right to intervene militarily in the territory of another state simply because there are individuals there with a passport issued by that state or who are nationals of the state.

"Attempts to apply such a doctrine have plunged Europe into war in the past... And we have reason to remember how Hitler used this very doctrine little more than half a century ago to undermine and attack substantial parts of central Europe."

Georgian and Russian troops faced each other in the South Ossetian capital Tskhinvali, which both sides claimed to have under their command. Exchanges of artillery fire killed 20 and injured 150 people, according to a South Ossetian spokeswoman.

Georgia's President Mikheil Saakashvili said on BBC television that Russia was pursuing a strategy aimed at "annihilation of a democracy on their borders". Georgia has declared a "state of war" and is recalling 2,000 troops from duty in Iraq to confront Russia in South Ossetia, but has also called for an immediate ceasfire.

Vladimir Putin, Russia's Prime Minister, defended the military campaign as he visited Vladikavkaz, close to the border with South Ossetia. He accused Georgia's "criminal" leadership of embarking on genocide against the people of Ossetia and said that Russia's actions were "absolutely well-founded and legitimate and moreover necessary".

In an ominous turn, Mr Putin warned that it was hard to imagine South Ossetia ever returning to Georgian control. Many in Tbilisi fear that Moscow is intent on re-writing the map of the Caucasus to incorporate South Ossetia and Abkhazia into Russia.

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