The diplomats may still be talking of peace, but from the front line deep inside the pro-Moscow breakaway republic of South Ossetia, a long-feared war between Russia and NATO-leaning Georgia appears to be under way.
At stake are Russia's already strained relations with the West, which backs Georgia, as well as Georgian President Mikhael Saakashvili's hopes of leading his country into the NATO alliance within the next year. An extended conflict might also hit global energy prices, if a crucial pipeline that carries Caspian oil and gas through Georgia to Western markets should be threatened.
After weeks of escalating skirmishes along the frontier between Georgia and South Ossetia, Georgian forces launched a full-scale invasion on Friday. By nightfall, they claimed to have occupied the capital, Tskhinvali, and about 70 percent of the rebel republic's territory.
A Georgian military spokesman said the fighting would go on until "constitutional order" was restored, meaning Tbilisi's full control. South Ossetia's rebel president, Eduard Kokoity, was quoted by Russian state TV as saying that 1,400 civilians died Friday in the Georgian military offensive.
But hopes of a swift Georgian victory -- on a day when the world's attention was diverted by the opening of the Beijing Olympics -- disappeared when armored elements of the Russian 58th Army poured through the Roki Tunnel, which separates the Russian republic of North Ossetia from South Ossetia, and Russian fighter planes began pounding Georgian positions in and around the rebel republic.
"During the whole day, Russian jet planes have been continuously attacking Georgian towns," President Saakashvili told journalists in Tbilisi. "They have been continuously attacking the town of Gori, in the middle of Georgia, which has nothing to do with South Ossetia."
Both sides blamed the other for starting the conflict.
Moscow has long supported South Ossetia and another Georgian rebel statelet, Abkhazia, and maintains a contingent of peacekeeping troops in both. The two republics won de facto independence through bitter civil wars in the early 1990s, and have since lived in legal limbo, unrecognized by the world community, which supports Georgia's claim of sovereignty over the whole territory of Soviet-era Georgia.
But two key developments have pushed these formerly "frozen conflicts" into the spotlight in recent months. The West's backing for Kosovo's independence from Serbia earlier this year, over Russian objections, created what Moscow calls a precedent for other breakaway territories. And the US-backed push to expand NATO into the former Soviet Union, taking in Ukraine and Georgia, has met ferocious resistance in Moscow. For Russia, the existence of breakaway territories in Georgia is a prime argument, frequently repeated by Mr. Medvedev to Western leaders, against Georgia's admission to NATO.
"Russia cannot allow Georgia to solve the South Ossetia problem by military means," says Irina Zvigelskaya, an expert with the independent Center for Strategic and International Studies in Moscow. "Of course the deaths of Russian peacekeepers and the destruction caused by the invading Georgians is an important reason why Medvedev has ordered Russian forces to intervene in the conflict. But there are bigger strategic reasons behind that. Moscow cannot let Saakashvili succeed in his gamble."
Zurab Totalidze, a watchman near the Georgian city of Gori, says he witnessed an alleged Russian plane drop bombs on a telephone installation. "It happened so fast, I didn't have time to be scared," he says.
Information from the conflict zone was contradictory and sketchy, but Russian media were reporting Friday night that Georgia may have blinked in the conflict and begun pulling its forces out of Tskhinvali.
Western news agencies quoted a South Ossetian website as saying that Russian armored vehicles were inside Tskhinvali and the Georgian forces were starting to retreat.
Saakashvili called on the Georgian Army to mobilize up to 100,000 reservists, while the chief of Georgia's security council, Kakha Lomaia, said that Georgia plans to withdraw its 1,000 troops currently serving with the US-led coalition in Iraq to meet urgent national security needs at home.
"It is absolutely clear that this was a long-planned offensive by Georgia against South Ossetia, not a spontaneous action," says Ms. Zvigelskaya. "But the entry of Russian forces into the conflict is a worst nightmare scenario. Georgian leaders may have thought they could achieve a quick fait accompli, but now we are looking at the specter of a long conflict with much destruction and many victims."
State Department spokesman Gonzago Gallegos said Friday that Washington has sent its own representative to the region to press for an immediate cease-fire in the fast-escalating conflict. "We call on all sides, including Georgians, South Ossetians, and Russians, to bring tensions down to avoid [bringing about] a conflict," he said.
In an interview with the BBC Friday, Saakashvili accused Russia of provoking the conflict by massing its troops along the border for the past several months.
"They have been calling it training exercises, but they have not been concealing the fact that they are training these troops for use inside Georgia,: he said.
"The way the escalation went was, we came first under extensive artillery barrage from the separatists, but in the end, I was told that Russian armored vehicles started to cross the Georgian border," he said. "And that was exactly the moment when I had to take this decision to fire back."
Russia denies Saakashvili's version, and has accused Georgia of breaking nonviolence agreements made after South Ossetia won its war of independence against Georgia in 1992. President Dmitri Medvedev, emerging from a meeting of the Kremlin's secretive Security Council on Friday, said he was appalled by the reported deaths of 10 Russian peacekeeping soldiers and scores of South Ossetian civilians -- about 90 percent of whom hold Russian passports -- in the course of the day's fighting. "It is my duty as president of the Russian Federation to protect the lives and dignity of Russian citizens, wherever they may be," Mr. Medvedev said.
Russian foreign minister Sergei Lavrov, in an emotional speech, accused Georgia of committing atrocities against the ethnic Ossetians who inhabit the territory. "It was absolutely unacceptable to see residential quarters shelled, to see a humanitarian convoy that was trying to reach the people in need bombed from the air," he said. "Many villages, including those outside the zone of conflict, are being attacked by the Georgian troops using artillery and tanks".