Georgia has called for a ceasefire after Russian bombers struck deep inside its territory.

US President George W Bush said Russian attacks on Georgia were a "dangerous escalation" of the crisis and urged Moscow to halt the bombing immediately.

But Russian President Dmitry Medvedev has said there will be no ceasefire until Georgian troops pull out of the disputed border region of South Ossetia.

Russian troops poured into South Ossetia on Friday, hours after Tbilisi launched a major offensive to take back control of the province from pro-Russian separatists.

Moscow has accused the Georgians of carrying out "ethnic cleansing and genocide" in the region.

Russian officials say the death toll stands at 2,000 and 30,000 refugees from South Ossetia have fled to Russia. The superpower says two of its warplanes have been shot down, 13 of its soldiers killed and 70 wounded.

Georgian President Mikheil Saakashvili said: "I call for an immediate ceasefire. Russia has launched a full scale military invasion of Georgia."

Russian jets have carried out up to five raids on the Georgian town of Gori, close to the conflict zone in South Ossetia. At least one bomb hit an apartment block, killing five people.

Mr Bush said: "The attacks are occurring in regions of Georgia far from the zone of conflict in South Ossetia. They mark a dangerous escalation in the crisis."

In a telephone call to Mr Bush, Mr Medvedev "stressed that the only way out of the tragic crisis provoked by the Georgian leadership is a withdrawal by Tbilisi of its armed formations from the conflict zone," a Kremlin statement said.

Abkhazia, another pro-Russian enclave in Georgia, has reportedly begun an operation to drive out Georgian forces, possibly opening a second front against Tbilisi.

Georgia has claimed Russian planes targeted a vital pipeline carrying oil to the West from Asia but had missed.

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