Georgia said a Russian air raid had "devastated" the Black Sea port of Poti. Russian jets have also carried out up to five raids on mostly military targets around the Georgian town of Gori.
Hours later, Vladimir Putin, the Russian prime minister, touched down in North Ossetia and described Russia's military intervention as "well-founded, legitimate and even necessary".
Al Jazeera's Jonah Hull, reporting from Gori, 30km outside South Ossetia, said: "Nobody here suspected it [Gori] would come under attack.
The Reuters news agency reported that at least one bomb hit an apartment block, killing five people.
"Civilians were hit very hard by these attacks, allegedly targeting military facilities but not doing a very good job of it," Hull reported.
|Russian jets attacked targets around
the Georgian town of Gori [Reuters]
"Russia says it is bombing Georgia into peace."
Russian tanks and troops surged into South Ossetia late on Thursday to repel a Georgian offensive aimed at reclaiming the region amid fighting that was said to have left hundreds dead.
Georgian and South Ossetian forces both claim that Tskhinvali, the South Ossetian capital, is under their control, and on Saturday Russia said that it had "liberated" the city from Georgia.
"Tactical battalions have completely liberated Tskhinvali from Georgian military forces," General Vladimir Boldyrev, head of Russia's ground forces, was quoted as saying by Russian news agencies.
The Moscow-backed administration in South Ossetia said 1,600 people had been killed since Georgia launched its offensive on Tskhinvali, but Saakashvili dismissed the claim as a "truly Soviet-style disinformation campaign".
Later, Russia's ambassador to Georgia said "at least 2,000" civilians had been killed in Tskhinvali.
World leaders, fearing a return to the Caucusus wars of the 1990s, have stepped up calls for an end to the conflict.
George Bush, the US president, said attacks by Russia on Georgia outside the war zone of South Ossetia marked a "dangerous escalation" of the crisis and urged Moscow to halt the bombing immediately.
"I'm deeply concerned about the situation in Georgia," Bush said. "The attacks are occurring in regions of Georgia far from the zone of conflict in South Ossetia. They mark a dangerous of escalation in the crisis."
Dmitry Medvedev, the Russian president, told Bush by telephone that only a pullout by Georgian troops from the conflict zone would end the fighting, according to a news release from the Kremlin.
"The Russian president has specifically stressed that the only way out from the tragic crisis provoked by the Georgian leadership is a withdrawal by Tbilisi of its armed formations from the conflict zone," the release said.
Sergei Lavrov, the Russian foreign minister, has said Moscow was not seeking all-out war with Georgia.
Ivan Safranchuk, a military analyst with the Moscow-based Centre for Defence and Information, told Al Jazeera: "There is no full-scale war and Russia isn't going to make a full-scale war. Russia is just showing its willingness to defend its citizens."
|South Ossetia claims 1,600 people
have been killed in Tskhinvali [AFP]
Russia is the main backer of the South Ossetian separatists and the majority of the region's population, who are ethnically distinct from Georgians, have been given Russian passports.
"Russia is saying that it is actually responding to a direct attack on its citizens and on its 'peace keepers' in South Ossetia," Alexander Nekrassov, a London-based Russian analyst, told Al Jazeera.
"This is a difficult legal situation here because techinically speaking South Ossetia is in the territory of Georgia, so any big Russian troop movement can be interpreted as an invasion of Georgia."
On Saturday, Poland called for an emergency EU summit to discuss the escalating conflict.
As both sides sought to influence the world powers, Dmitry Rogozin, Russia's ambassador to Nato, said that "genocide" was taking place in South Ossetia.
"What we have in South Ossetia can only be called ethnic cleansing and genocide," he told reporters in Brussels.
Even as the South Ossetian conflict mounted, Georgia faced possible fighting on two fronts.
The foreign minister of Georgia's other breakaway province of Abkhazia said its separatist forces had launched air and artillery strikes to drive Georgian troops from the region.
Sergei Shamba said Abkhazian forces intended to push Georgian troops out of the Kodori Gorge. The northern part of the gorge is the only area of Abkhazia that has remained under Georgian government control.
A spokesman for the pro-Georgian Abkhaz government-in-exile said the bombings had been carried out by Russian warplanes.
"Earlier today ... Russian jet fighters bombed two villages in the upper part of the gorge," Raul Kiria, the government in exile's spokesman, said.