A woman walks past a destroyed building last week in Tskhinvali, in the Georgian breakaway province of South Ossetia. Russian military authorities issued a flurry of conflicting reports Sunday about whether Russian troops had begun to pull out of South Ossetia, one of Georgia's two separatist provinces.

Gori, Georgia ? Russia’s president promised to start withdrawing forces from positions in Georgia today, but suggested they could stay in the breakaway region at the heart of the fighting that has reignited Cold War tensions.

Top American officials said Washington would rethink its relationship with Moscow after its military drive deep into its much smaller neighbor and called for a swift Russian withdrawal.

“I think there needs to be a strong, unified response to Russia to send the message that this kind of behavior, characteristic of the Soviet period, has no place in the 21st century,” Defense Secretary Robert Gates said Sunday.

But neither Gates nor Secretary of State Condoleezza Rice would be specific about what punitive actions the U.S. or the international community might take.

Bolstered by Western support, Georgia’s leader vowed never to abandon its claim to territory now firmly in the hands of Russia and its separatist allies, even though he has few means of asserting control. His pledge, echoed by Western insistence that Georgia must not be broken apart, portends further tension over separatist South Ossetia and Abkhazia.

In Gori, a strategic central city in the small former Soviet republic, there were signs of a looser Russian grip – and scenes of desperation as Georgians crowded around aid vehicles and grasped for loaves of bread.

Georgia hit the Russia-backed separatist region of South Ossetia with a massive barrage on Aug. 7, and Russian troops rolled in, advancing far into the Caucasus Mountain nation and raising fears of a long-term occupation of a country at the center of a power struggle between a resurgent Russia and the West.

The troops would leave, a Russian lawmaker said, “sooner or later.”

“But how much time it will take, it depends, definitely, on how Georgians will continue to behave,” said the lawmaker, Konstantin Kosachev, chairman of a Russian parliament foreign affairs committee.

Rice, who is flying to Europe today to talk with NATO allies about what message the West should send to Russia, said Russia can’t use “disproportionate force” against its neighbor and still be welcomed into the halls of international institutions.

“It’s not going to happen that way,” she said. “Russia will pay a price.”

French President Nicolas Sarkozy warned Russia’s president of “serious consequences” in Moscow’s relations with the European Union if Russia does not comply with the cease-fire accord.

Later, Sarkozy said in an opinion article published on Le Figaro newspaper’s Web site that if Russia did not “rapidly and totally” follow the pullout specified in the cease-fire, he would “have to call an extraordinary meeting of the Council of the European Union to decide what consequences to draw.”

Medvedev had told Sarkozy that Russian troops would begin pulling back today, headed toward South Ossetia. He stopped short of promising they would return to Russia.

The New York Times, citing anonymous U.S. officials who were familiar with intelligence reports, reported Sunday that the Russian military moved missile launchers into South Ossetia on Friday.

The U.S. officials told the Times that Russia deployed several SS-21 missile launchers to positions north of Tskhinvali, the South Ossetian capital. That would put the missiles within range of Georgia’s capital, Tbilisi, the Times reported on its Web site.

The EU-backed cease-fire agreement calls for Georgian and Russian troops to withdraw to the positions they held before fighting broke out Aug. 7.

But Medvedev’s silence on South Ossetia has fueled fears that Russia could annex the region, which – like Abkhazia – broke from Georgia government control in the 1990s and has declared independence. Getting Abkhazia alone would increase the length of Russia’s Black Sea coast by more than 25 percent.

“Georgia will never give up a square kilometer of its territory,” Georgian President Mikhail Saakashvili told a news conference alongside Germany’s Angela Merkel, the latest Western leader to visit Tbilisi and offer support for the country he has led on a pro-Western path, seeking to shake off a history of domination by Moscow.

“I expect a very fast, very prompt withdrawal of Russian troops out of Georgia,” Merkel said in a courtyard at Saakashvili’s official residence. She reiterated a Western promise that Georgia will eventually join NATO, but said she could not say when that would happen.