TBILISI, Georgia -- Western leaders warned Russia on Wednesday to "change course," hoping to keep a conflict that already threatens a key nuclear pact and could even raise U.S. chicken prices from blossoming into a new Cold War.

Meanwhile, Georgia slashed its embassy staff in Moscow to protest Russia's recognition of the two separatist enclaves that were the flashpoint for the five-day war between the two nations earlier this month.

The tensions have spread to the Black Sea, which Russia shares unhappily with three nations that belong to NATO and two others that desperately want to, Ukraine and Georgia. Some Ukrainians fear Moscow might set its sights on their nation next.

In moves evocative of Cold War cat-and-mouse games, a U.S. military ship carrying humanitarian aid docked at a southern Georgian port, and Russia sent a missile cruiser and two other ships to a port farther north in a show of force.

The maneuvering came a day after Russian President Dmitry Medvedev had said his nation was "not afraid of anything, including the prospect of a Cold War." For the two superpowers of the first Cold War, the United States and Russia, repercussions from this new conflict could be widespread.

Russia's agriculture minister said Moscow could cut poultry and pork import quotas by hundreds of thousands of tons, hitting American producers hard and thereby raising prices for American shoppers.

Russians sometimes refer to American poultry imports as "Bush's legs," a reference to the frozen chicken shipped to Russia amid economic troubles following the 1991 Soviet collapse, during George H.W. Bush's presidency.

And a key civil nuclear agreement between Moscow and Washington appears likely to be shelved until next year at the earliest.

On the diplomatic front, the West's denunciations of Russia grew louder.

Britain's top diplomat equated Moscow's offensive in Georgia with the Soviet tanks that invaded Czechoslovakia to crush the Prague Spring democratic reforms in 1968, and demanded Russia "change course."

"The sight of Russian tanks in a neighboring country on the 40th anniversary of the crushing of the Prague Spring has shown that the temptations of power politics remain," Foreign Secretary David Miliband said.

Western leaders have accused Russia of using inappropriate force when it sent tanks and troops into Georgia earlier this month. The Russian move followed a Georgian crackdown on the pro-Russian South Ossetia.

Many of the Russian forces that drove deep into Georgia after fighting broke out Aug. 7 have pulled back, but hundreds are estimated to still be manning checkpoints that Russia calls "security zones" inside Georgia proper. German Chancellor Angela Merkel pressed Russian President Dmitry Medvedev in a phone call to immediately fulfill the EU-brokered cease-fire by pulling all troops out of Georgia.

The Kremlin rejected Western criticism, and Tuesday even suggested the conflict could spread. It starkly warned another former Soviet republic, tiny Moldova, that aggression against a breakaway region there could provoke a military response.

French President Nicolas Sarkozy accused Russia of trying to redraw the borders of Georgia. His foreign minister went further, suggesting Russia had engaged in "ethnic cleansing" in South Ossetia, one of the two Georgian rebel territories.

And the seven nations that along with Russia make up the G-8 issued a statement that underlined Russia's growing estrangement from the West.

The seven -- United States, Britain, France, Canada, Germany, Japan and Italy -- said Russia's decision to recognize South Ossetia and Abkhazia as independent countries violated the Georgia's territorial integrity.

Two weeks ago, officials had told The Associated Press that the G-7 were weighing whether to effectively disband what is known as the G-8 by throwing Moscow out.

Georgia's prime minister put damage from the Russian war at about $1 billion but said it did not fundamentally undermine the Georgian economy. Georgia, which has a national budget of about $3 billion, hopes for substantial Western aid to recover.

The United Nations has estimated nearly 160,000 people had to flee their homes, but hundreds have returned to Georgian cities like Gori in the past week.

In the Georgian capital of Tbilisi, boxes of aid were sorted, stacked and loaded onto trucks Wednesday for some of the tens of thousands of people still displaced by the fighting. Some boxes were stamped "USAID -- from the American People."

In the Black Sea, the U.S. Coast Guard cutter Dallas, carrying 34 tons of humanitarian aid, docked in Batumi. The missile destroyer USS McFaul was there earlier this week delivering aid, and the U.S. planned to leave it in the Black Sea for now.

A spokesman for Putin, quoted by Interfax news agency, observed: "Military ships are hardly a common way to deliver such aid."

The U.S. has used military ships to deliver humanitarian aid before, including in the aftermath of the 2004 Asian tsunami.

The U.S. Embassy in Georgia had earlier said the Dallas was headed to the port city of Poti but then retracted the statement. A Georgian official said the port in Poti could have been mined by Russian forces.

Poti's port reportedly suffered heavy damage from the Russian military. In addition, Russian troops have established checkpoints on the northern approach to the city, and a U.S. ship docking there could have been seen as a direct challenge.

Meanwhile, the Russian missile cruiser Moskva and two smaller missile boats anchored at the port in Sukhumi, the capital of Abkhazia, some 180 miles north of Batumi. The Russian Navy says the ships will be involved in peacekeeping operations.

Russian Col. Gen. Anatoly Nogovitsyn warned that NATO has already exhausted the number of forces it can have in the Black Sea, according to international agreements, and warned Western nations against sending more ships.

"Can NATO -- which is not a state located in the Black Sea -- continuously increase its group of forces and systems there? It turns out that it cannot," Nogovitsyn was quoted as saying Wednesday by Interfax.