After taking control of Georgia`s breakaway region of South Ossetia, Russian warplanes carried out fresh bombing raids in Georgia, Georgia`s foreign ministry said.
With Russia saying more than 2,000 people have been killed, Europe led diplomatic efforts to end the conflict with the French and Finnish foreign minister holding talks in Tblisi on Monday ahead of a meeting with Russia`s President Dmitry Medvedev in Moscow on Tuesday.
US President George W. Bush, Georgia`s strongest western ally, told Russia`s Prime Minister Vladimir Putin that the Russian offensive was "unacceptable".
"More than 50 Russian warplanes are flying over Georgia. Tbilisi was bombed. Bombs hit the village of Kojori and Makhata mountain," the foreign ministry in Tblisi said.
Russian planes bombed radars at Tbilisi airport and hit civilian targets in the Georgian city of Gori, an interior ministry spokesman said.
Russian planes had already bombed a special forces base and an air traffic control centre in the Tbilisi suburbs, the spokesman said.
Explosions could be heard from the centre of the capital.
Three Russian soldiers were killed and another 18 wounded by Georgian forces in South Ossetia on Monday, despite Georgia saying it had withdrawn its forces, Russia`s Interfax news agency quoted a South Ossetian spokesman as saying.
Russia, which has already moved battleships to the Black Sea, is preparing to deploy 9,000 troops to bolster its forces inside a second separatist Georgian region, Abkhazia, a military spokesman was quoted as saying by Interfax.
It will also send more than 350 armoured vehicles to add to what is officially a Russian peacekeeping force in the breakaway region, the Russian spokesman, Alexander Novitsky, was quoted as saying.
Russian forces in Abkhazia on Monday issued an ultimatum to Georgian forces demanding they lay down their weapons, their commander was quoted as saying by Interfax.
Georgia`s interior ministry denied on Monday that Georgian soldiers were cornered by rebels in a part of Abkhazia region, saying all attacks in the area had been repelled.
"There were several attacks on the Kodori Gorge, all of them repelled," interior ministry spokesman Shota Utiashvili said in a televised briefing.
Georgian President Mikheil Saakashvili said late Sunday that Russian tanks were on Georgian territory outside South Ossetia the interior ministry said a "massive" aerial bombardment of the centre of Gori was taking place.
"Gori is being bombed massively from the air and from artillery as well," said the spokesman, who added that the government had reports that Russian troops and tanks were preparing a ground attack.
Moscow said it had sunk a Georgian naval vessel and taken control of most of South Ossetia from Georgian forces. The Russian foreign ministry said Georgia still had soldiers and tanks in the area however.
Russia pursued its offensive despite Georgia saying it had ended its push on South Ossetia.
"Georgia expresses its readiness to immediately start negotiations with the Russian Federation on a ceasefire and termination of hostilities," an official Georgian statement said.
Russia disputed this, however, with the commander of the Russian peacekeepers in South Ossetia saying they had come under attack by Georgian forces again early Monday.
"In certain zones (near Tskhinvali) Russian peacekeepers met active confrontation" overnight, Marat Kulakhmetov told Interfax.
The United States has strongly criticised Russia.
Bush said Monday he had told Russian Prime Minister Putin that the violence in Georgia was "unacceptable".
Vice President Dick Cheney told Saakashvili in a telephone conversation "that Russian aggression must not go unanswered," his office said in a statement.
The French and Finnish foreign ministers Bernard Kouchner and Alexander Stubb arrived in Tbilisi on Sunday to spearhead mediation efforts.
"We must find the means for an immediate ceasefire, accepted by both sides," Kouchner told reporters after meeting with Saakashvili.
French President Nicolas Sarkozy is expected to head to Moscow Tuesday to "try to finalise" a ceasefire with Georgia, Kouchner told French radio from Tbilisi
The European Union-backed plan calls for an immediate ceasefire, medical access to victims, controlled withdrawals of troops on both sides and eventual political talks.
The two ministers were to meet Medvedev in Moscow, where French President Nicolas Sarkozy was also due Moscow.
European Union foreign ministers are to hold a crisis meeting to discuss the bloc`s response to the conflict on Wednesday in Brussels, an EU source told AFP.
Russia sent thousands of troops, tanks and air support into South Ossetia on Friday after Georgia launched an offensive to seize control of the province, which broke from Georgia in the early 1990s.
The conflict has already forced about 40,000 people from their homes in areas around the conflict zone, an International Committee of the Red Cross spokeswoman told AFP.
While Russia put the death toll in South Ossetia at 2,000, estimates of the toll in Georgia ranged from 92 to 150.
South Ossetia, a patchwork of ethnic Georgian and Ossetian settlements in the mountainous north of the country, has a population of about 70,000, many of whom have been granted Russian passports.