Russian Prime Minister Vladimir Putin accused the United States on Thursday of instigating the fighting in Georgia and said he suspects a connection to the US presidential campaign - a contention the White House dismissed as "patently false." In a decision he said was unrelated to unraveling Russia-US ties, Putin also ordered that 19 American poultry producers be barred from selling their products to Russia. He said the unnamed companies ignored demands that they correct alleged deficiencies. 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 US political motive. "We have serious grounds to think that there were US citizens right in the combat zone" during Russia's war with the US-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."