Putin, the former president and architect of an assertive foreign policy that has stoked East-West tension, suggested in an interview with CNN that there was an American presence amid the combat with a potential domestic U.S. political motive.
"We have serious grounds to think that there were U.S. citizens right in the combat zone" during Russia's war with the U.S.-allied ex-Soviet republic, he said the interview broadcast on state-run Russian television. "And if that's so, if that is confirmed, it's very bad. It's very dangerous."
Putin's acid attack on the United States came as Moscow's bid to redraw Georgia's borders hit an obstacle among its Asian allies who refused to recognize the two Russian-backed breakaway regions of Georgia. France, meanwhile, said the European Union is considering sanctions against Russia for its conduct in the Caucasus.
Putin said that Russia had hoped the U.S. would restrain Georgia, which Moscow accuses of starting the war by attacking South Ossetia on Aug. 7. Instead, he suggested the U.S. encouraged the nation's leadership to try to rein in the separatist region by force.
"The American side in fact armed and trained the Georgian army," Putin said. "Why hold years of difficult talks and seek complex compromise solutions in interethnic conflicts? It's easier to arm one side and push it into the murder of the other side, and it's over.
"It seems like an easy solution. In reality it turns out that it's not always so," he said.
The United States has close ties with the Georgian government and has trained Georgian units. The Pentagon has said that the U.S. had about 130 trainers in Georgia when the fighting erupted earlier this month, including a few dozen civilians who were all working to prepare the Georgian forces for deployment to Iraq.
But Russian officials have made statements aimed to convey the idea that Americans may have directly supported Georgia's offensive.
At a briefing Tuesday, the deputy chief of Russian military general staff, Col. Gen. Anatoly Nogovitsyn, showed off a color copy of what he said was a U.S. passport found in a basement in a village in South Ossetia among items that belonged to Georgian forces.
"We found a passport for Michael Lee White," Nogovitsyn said. "He's a Texan."
The U.S. Embassy in Georgia said it had no information on the matter.
In an interview with France 24 to be aired Friday, Georgian President Mikhail Saakashvili said there were no American "commanders or even advisers" in the conflict zone. He said the conflict had nothing to do with the U.S., but "the aggression of the Russians."
Putin appeared to link claims of an American presence amid the combat with a potential domestic U.S. political motive.
"If my guesses are confirmed, then that raises the suspicion that somebody in the United States purposefully created this conflict with the aim of aggravating the situation and creating an advantage ... for one of the candidates in the battle for the post of U.S. president."
Putin did not name a party or candidate. Some pro-Kremlin Russian politicians have claimed U.S. Republicans hoped the war would help keep Democrat Barack Obama out of the White House by fomenting concern among voters over security, which some of the Russians consider to be a strong-suit of Republican candidate John McCain, a strong Kremlin critic.
White House press secretary Dana Perino called Putin's contentions "patently false." She said "it also sounds like his defense officials who said they believe this to be true are giving him really bad advice."
She added: "To suggest that the United States orchestrated this on behalf of a political candidate just sounds not rational."
Perino said Russia is facing the consequences of a diminished global reputation and that "there will be other" consequences as well. She refused to say what they would be and said there is no timetable.
The Russian leader maintained that the poultry decision was unrelated to the Georgia issue. He said that the 19 producers ignored the demands to correct the problems following inspections. He said another 29 producers would receive warnings.
"We try and keep our industry out of politics and into marketing opportunities, but sometimes it's very difficult to separate the two," said Jim Sumner, president of the U.S.A. Poultry & Egg Export Council. He said Russia is a major market for American producers.
U.S. producers supply nearly 75 percent of the total poultry import quota set by Russia, which stands at 1.2 million tons. Russia represented the largest export market for chicken broilers made by U.S. producers in the first half of this year, Sumner said.
Sumner said he expected the alleged plant deficiencies to be corrected within weeks or a few months and said the stoppage would not have a major impact on U.S. producers.
Russia is an important market for many poultry producers, including the nation's largest chicken producer, Pilgrim's Pride Inc., as well as Sanderson Farms Inc. and Tyson Foods Inc., the world's largest meat company.
Shares of many meat producers, including top hog producer Smithfield Foods Inc., tumbled Thursday on worries about potential cuts by Russia.
"At this point if Russia were to walk back from certain agreements they have made, it would clearly delay any future aspirations they have of joining the World Trade Organization," said Sean Spicer, spokesman for U.S. Trade Representative Susan Schwab.
In Tajikistan, China and four Central Asian nations criticized the West, but wary of separatists at home, they stopped short of heeding Russia's call to recognize the breakaway Georgia regions of South Ossetia and Abkhazia.
Moscow had appealed to the Shanghai Cooperation Organization - whose members are Russia, China, and four Central Asian countries of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan - for unanimous support of Moscow's response to Georgia's "aggression."
Alexei Malashenko, an analyst at the Carnegie Moscow Center, said the summit highlighted Russia's isolation.
"The Soviet Union was not so alone even in 1968," he said on Ekho Moskvy radio, referring to the Soviet invasion of Czechoslovakia.
Western leaders have added condemnation of Russian recognition to their accusations that Moscow used disproportionate force in its Georgia offensive and has fallen far short of its withdrawal commitments under an EU cease-fire deal.
The EU is "trying to draw up a strong text signifying our unwillingness to accept" Russia's stance, French Foreign Minister Bernard Kouchner said Thursday. "Sanctions are being considered ... and many other means as well," Kouchner said.
The Foreign Ministry said later that France was not behind a sanctions proposal.
Associated Press Writers Peter Leonard and Olga Tutubalina in Dushanbe, Tajikistan; Jim Heintz and Misha Dzhindzhikhashvili in Tbilisi, Georgia; and Catrina Stewart, Nataliya Vasilyeva, David Nowak, Doug Birch and Mansur Mirovalev in Moscow, Natasha Metzler in Washington and business writer Emily Fredrix in Milwaukee contributed to this report.