Moscow/Tbilisi - Russia on Sunday intensified airstrikes and a naval blockade against Georgia, as international diplomats sought ways to bring a ceasefire to the Caucasus province South Ossetia.

Three Russian air force Su-25 bombers struck an airfield adjacent to a military aircaft factory outside the Georgian capital Tbilisi shortly after dawn, causing damage but inflicting no casualties, a senior Georgian official said.

Russian bombers also struck a Georgian military base near the town of Bolnisi and in the remote Kodori valley near the border of Abkhazia, Georgia's Rustaveli-2 television reported.

The war widened on Saturday with Abkhazia, like South Ossetia a separatist Georgian province supported by Moscow, attacking Georgian forces.

Warships from Russia's Black Sea fleet by Sunday morning had clamped down a naval blockade on Georgia's coast line, turning back "several civilian ships," said Aleksander Lomaia, Georgia's National Security Council Chief, in a statement.

Among freighters halted with warning shots was a Moldovan-flagged vessel carrying wheat to the port Poti, threatening Georgia's food supplies, Lomaia claimed.

Georgian intelligence gave the elements of the Russian squadron as three amphibious assault vessels, two anti-submarine warfare vessels, a reconnaissance ship, two minesweepers, two missile boats, and a missile cruiser.

The Russian flotilla is substantially larger than Georgia's tiny navy, currently bottled up in Poti, military observers said.

The site of the fiercest ground fighting over the last three days, the unofficial South Ossetian capital Tskhinvali, saw infantry battles throughout the night as Russian forces engaged Georgian troops holding heights overlooking the town.

Heavy artillery fire on the city, a feature of fighting since the war's outbreak, had practically halted by early Sunday morning, according to a South Ossetia army statement.

Some civilians remained trapped in the city, most of whose buildings are now badly damaged or destroyed, witnesses said.

Corpses in some cases three days old still were lying in Tskhinvali's streets, as artillery fire from both sides made burial impossible, the Interfax news agency reported.

Georgia gave its military losses as of Saturday at some 50 men dead and 450 wounded. Russia had admitted to 12 men dead and 150 injured.

Estimates of civilian dead in the fighting have exceeded 1,600 people. The Tskhinvali town hospital alone as of Sunday morning was treating 200 injured and had more than 50 dead in its morgue, according to the report.

Some 2,000 Russian paratroopers and Spetsnaz special forces infantry backed by artillery and tanks threw Georgian forces out of the town on Saturday in intense house to house fighting.

Russian ground forces in Ossetia numbered in excess of 6,000 men with the strength expected to rise as the Kremlin rushed more reinforcements to the region, Georgian officials said.

Russian Prime Minister Vladimir Putin during a Saturday visit to Russia's 58th Army headquarters in Vladkavkaz said the Kremlin's intention was to push out or destroy all Georgian forces in South Ossetia. He justified the Russian offensive as part of a peacekeeping operation.

Georgian President Mikheil Saakashvili the same day accused Russia of conducting all-out war against Georgia, pointing to airstrikes and a naval blockade outside the South Ossetia region.

The international community has failed to produce any practical means towards reaching a ceasefire in the four-day-old conflict. The UN's Security Council on Saturday met in emergency session on South Ossetia and, for the third day in a row, was unable to decide even on a position statement, because of differences between Russia and the US.

Russia's government was by the weekend moving quickly towards establishing even tighter links with the South Ossetia regime, with Putin announcing Moscow would spend a half billion dollars to rebuild Tskhinvali, and provincial Russian agencies offering aid to an estimated 34,000 refugees from the fighting.

Russia not only would provide the refugees food and shelter, but make sure that children now living in temporary housing or with relatives on the Russian side of the border, would start their school year on time, Putin said during a Sunday visit to the Russian city Gorkiy.

Georgia on Saturday said it was recalling a 2,000-man infantry brigade currently serving in Iraq and accounted the Georgian army's most effective fighting force.

Its return home would, however, be problematic, with a Russian blockade likely to prevent shipment of the brigade's heavy equipment home by sea, and the Russian air force potentially able to intercept any passenger flight from Iraq to Georgia.

Georgian media reported that US aircraft might carry the Georgian infantrymen home, placing Washington and Moscow on a collision course.

Another potential flashpoint for a widening of the war was in the Black Sea near the Georgian port Batumi, where Turkish warships had taken up station. There had been no reports by Sunday of contact between the Turks, and elements of the Russian navy operating further south.

Georgia's Olympic team on Sunday reversed a Saturday decision to quit the Beijing Olympics and would compete in China as planned, according to an Interfax report. (dpa)