Russian troops took most of the capital of the separatist Georgian region of South Ossetia on Sunday after a three-day battle but the United States condemned Moscow's "dangerous and disproportionate" action.
Russia poured troops and tanks across its southern border into Georgia and bombed Georgian targets after Tbilisi attempted on Thursday evening to retake South Ossetia, a small pro-Russian province which broke away from Georgia in the 1990s.
In a possible opening of a second front in the conflict, Georgia accused Russia of starting a military operation on Sunday in Abkhazia, another separatist region of Georgia to the west of South Ossetia. Moscow denied involvement.
The crisis has alarmed the United States, Georgia's main ally, and unnerved investors in Russia, who sold stocks and the rouble heavily on Friday on concerns the conflict could spiral.
The West is vying for influence with Russia over oil and gas supply routes in the region and Russia is rankled by Georgia's pro-Western policies and its drive for NATO membership.
Georgia and Russia have accused each other of causing widespread civilian casualties since the fighting began.
State-controlled Russian television repeatedly spoke of a "humanitarian catastrophe" in South Ossetia after the Georgian attack, with more than 2,000 dead and thousands homeless.
A Georgian government source said on Saturday that 129 Georgian civilians and military had been killed and 748 wounded, many because of Russian bombing inside Georgia. Russia denied hitting civilian targets.
Moving south from the Caucasus mountains, Russian forces took control on Sunday of most of Tskhinvali, the South Ossetian capital, which has been devastated by intense fighting.
Russia's military commander on the ground, Gen Anatoly Khrulyov, was wounded by shrapnel when his convoy came under Georgian fire, Russian agencies reported.
"As of today most of the city (Tskhinvali) is controlled by Russian peacekeeping forces,"Colonel-General Anatoly Nogovitsyn of the Russian General Staff, told a briefing in Moscow.
Georgia confirmed it forces were quitting the city.
Viewed from the town of Gori inside Georgian-controlled territory, Tskhinvali appeared quiet. A Reuters correspondent reported hearing only one burst of what sounded like artillery fire, though there were reports of isolated sniper fire.
The White House deplored Russia's action, which included bombing at least three Georgian targets outside South Ossetia.
President George W Bush's deputy national security adviser James Jeffrey told reporters in Beijing, where the president was attending the Olympics, that Moscow's actions could have a "significant long-term impact" on relations.
"We deplore the dangerous and disproportionate actions by Russian forces and we would be particularly troubled if these attacks are continuing now as the Georgians are pulling back," he said.
Pope Benedict called for an immediate halt to the fighting, expressing "profound anguish" that the violence had caused many innocent victims and forced many civilians to leave their homes.
Russian television showed what it said were pictures from Tskhinvali of burnt-out buildings, wounded civilians receiving medical treatment in basements and crying mothers complaining of a lack of food and water.
"The Georgian tanks fired at everything they saw, including women and children," one man said after his evacuation over the border to the Russian region of North Ossetia.
A woman evacuee clutching her two children said she feared the worst for her husband.
"It's so difficult to be here and know my husband is still in South Ossetia," she said.
In Geneva, the UN High Commissioner for Refugees Antonio Guterres expressed concern over the plight of thousands of civilians caught up in fighting in and around South Ossetia, a region of 70,000 people.
Russian Prime Minister Vladimir Putin cut short his visit to the Olympics and flew on Saturday to a field hospital in North Ossetia, visiting wounded troops and evacuees, and denouncing what he termed Georgia's "crimes against its own people".
Potentially widening the conflict, the Abkhaz leader Sergei Bagapsh said on Sunday he had ordered 1,000 troops to push Georgian forces out of the Kodori Gorge, a strategic pocket of territory in Abkhazia, and called up reservists.
Georgia denounced what it termed "new aggression" by Moscow in Abkhazia, a strip of land along the Black Sea coast which also broke away from Georgian control.
"They have started the operation to storm Kodori Gorge," Georgian Interior Ministry spokesman Shota Utiashvili said.
Russian general Nogovitsyn denied Moscow was taking part in any operation in Abkhazia beyond its agreed peacekeeping role.
"We are not going to undertake any actions which are going to lead to escalation of the situation in this region," he said.
Russia's navy also entered the conflict, deploying a flotilla off Georgia's Black Sea coast. There was no official comment on their mission but the Interfax news agency said they would stop weapons and military gear reaching Georgia by sea.