Footage reportedly shows Russian tanks entering South Ossetia
Russian forces are locked in fierce clashes with Georgia inside its breakaway South Ossetia region, reports say, amid fears of all-out war.
Moscow sent armoured units across the border after Georgia moved against Russian-backed separatists.
Russia says 12 of its soldiers are dead, and separatists estimate that 1,400 civilians have died.
Georgia accuses Russia of waging war, and says it has suffered heavy losses in bombing raids, which Russia denies.
Georgian President Mikhail Saakashvili says he is willing to agree an immediate ceasefire
Russian tanks have reportedly reached the northern suburbs of the regional capital, Tskhinvali, and there were conflicting claims about who was in control of the city.
"Now our peacekeepers are waging a fierce battle with regular forces from the Georgian army in the southern region of Tskhinvali," a Russian military official was quoted as saying by Moscow-based news agency, Interfax.
After days of exchanging heavy fire with the separatists, Georgian forces moved on Thursday night to regain control of the region, which has had de facto independence since a war against Georgia that ended in 1992.
I saw bodies lying on the streets, around ruined buildings, in cars. It's impossible to count them now
Fleeing resident Lyudmila Ostayeva, 50, told AP news agency: "I saw bodies lying on the streets, around ruined buildings, in cars. It's impossible to count them now. There is hardly a single building left undamaged."
International Red Cross spokeswoman Anna Nelson said it had received reports that hospitals in Tskhinvali were "overflowing" with casualties.
In other developments:
The UN Security Council fails to agree a statement on the crisis, despite holding a second session of talks on Friday evening
US Secretary of State Condoleezza Rice called on Russia to pull its troops out of Georgia and respect its territorial integrity
Georgia's president said his country was withdrawing half its contingent of 2,000 troops from Iraq to help deal with the crisis
Russia said it would cut all air links with Georgia from midnight on Friday
The European security organisation, the OSCE, warned that the fighting in South Ossetia could escalate into a full-scale war
The US and the EU were reported to be sending a joint delegation to the region to seek a ceasefire and Nato said it was seriously concerned
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