Russian troops and tanks entered the separatist province of South Ossetia by the hundreds on Saturday, with more soldiers expected to land in the disputed province of Abkhazia, further escalating the conflict with Georgia.

The latest offensive has apparently killed or wounded scores of civilians, but with the situation changing rapidly information was difficult to verify.

Georgia's President Mikhail Saakashvili has called for a ceasefire to stop the violence and said his country is in "a state of war."

Saakashvili told a news conference in Tbilisi on Saturday that that the warring parties should be separated.

The proposal would see Georgian troops withdraw from Tskhinvali, South Ossetia's provincial capital, and stop retaliating against shelling by Russian troops.

Meanwhile, Russia's Prime Minister Vladimir Putin called on Georgia to stop its "aggression against South Ossetia," where many residents have Russian passports and family within Russia's borders.

Putin said on Saturday that Russian actions are "totally legitimate" and claimed Georgia was the aggressor.

"We urge the Georgian authorities to immediately stop their aggression against South Ossetia, to stop all violations of all standing agreements on a ceasefire and to respect the legal rights and interests of other people," he said on state television from a Russian city near the separatist province.

Russia's President Dmitry Medvedev said his country is trying to get Georgia to withdraw its troops to the positions they held on Thursday.

A diplomatic delegation, including envoys from the European Union and the U.S., was reportedly heading to the region in an effort to quell the violence.

On Saturday, U.S. President George Bush strongly urged Russia to stop its military activities in Georgia.

"Georgia is a sovereign nation, and its territorial integrity must be respected," Bush said in Beijing.

"We have urged an immediate halt to the violence and a stand-down by all troops. We call for the end of the Russian bombings."

Medvedev reportedly told Bush the only solution is for Georgian troops to pull out of the conflict zone.

Daniel Kimmage, a regional analyst for Radio Free Europe, told CTV Newsnet that Russia will try to make as many gains that it can militarily before diplomatic efforts begin.

"It's really the military component that is at the forefront now, not so much the diplomatic effort," he said.

Abkhazia

Meanwhile, Russian warships are heading to the province of Abkhazia, bringing more soldiers to push back Georgian forces. Abkhazia occupies the western tip of Georgia, bordered by Russia and the Black Sea.

South Ossetia is located more to the centre of Georgia, sharing a border with Russia. It doesn't share a border with Abkhazia.

Most of the estimated 2,000 people to have died so far in the conflict are civilians. Georgian leaders have dismissed the death estimates, which have been provided by Russian military sources. They say very few civilians have died.

An estimated 30,000 refugees have fled to Russia from South Ossetia since Thursday.

Russia reports that two of its warplanes have been downed and 12 of its soldiers killed.

Russia sent its armed forces into South Ossetia on Friday in an attempt to counter a large-scale offensive by Georgia, which had lost control over the province following the breakup of the Soviet Union in the early 1990s. South Ossetia has declared independence, but no international government has recognized the declaration.

Georgia is friendly to the West and wants to join NATO. Saakashvili has vowed to bring South Ossetia and Abkhazia back under Georgian control, although he has also offered South Ossetia a form of autonomy within Georgia.

Meanwhile, Georgia's National Security Council has accused Russian troops of conducting "ethnic cleansing" in South Ossetia, where Georgians are a minority. Putin claimed Georgia was carrying out a "genocide."

With files from The Associated Press