U.S. Ambassador Thomas Pickering on Thursday ruled out any chance that the American government might contribute money to international financier George Soros' $100 million science foundation in Russia and the former Soviet republics. The funds of the International Science Foundation, created to provide opportunities for scientists to prevent their immigration, will be depleted at the end of 1995, said its director, Alex Goldfarb. Soros has said he will not put more money into the project unless governments contribute as well. During a tour of the foundation's headquarters in southern Moscow, Pickering said that U.S. aid "should not be competitive with what other governments or private individuals are doing," and "in principle, should be funding of last resort for projects of high priority for the American government.""This one is purely private," he said. "We have no plans to finance it."The foundation has already secured a $12.5 million commitment from the Russian government, as well as a total of $1.5 million from Ukraine and the Baltic states. Soros has said he will match the contributions. The foundation was started in late 1992 to prevent the "brain drain" of top scientists from the former Soviet Union by supporting research in the basic sciences. In 1993, about 40,000 scientists received money from the foundation, Goldfarb said. About $46 million will go to finance long-term research projects, with grants ranging from $10,000 to $100,000. Other projects include paying for scientists to attend international conferences and supplying libraries with scientific journals.Goldfarb used the occasion to distance himself from Soros' other major Russian foundation, the Cultural Initiative, which fired several staff members in May after an audit found that $14 million had been placed improperly in small Russian banks. The turmoil at the Cultural Initiative had caused alarm among the Science Foundation's grant recipients, he said. "Of course, when these things go to press it causes confusion, so people call us to say, 'Is it true that you stole money? Is it true that Soros is closing you down?'" Goldfarb said. "Because many people depend on us."He stressed that the science foundation had developed a system for distributing grants designed to minimize risk of abuse.