Russia's top prosecutor has joined a rapidly expanding investigation into allegations that Russian organized crime groups funneled billions of dollars through the Bank of New York in a vast money-laundering operation, officials here said today.

Russian officials had been conspicuously silent since word of the probe surfaced a week ago in New York. But with U.S. congressional hearings on the matter planned for next month, Acting Prosecutor General Vladimir Ustinov announced an investigation into reports that up to $15 billion may have passed through the bank as part of an effort to mask illegal profits as legitimate business proceeds. U.S. and British authorities are already investigating, but no charges have been filed thus far.

The alleged scheme would be the latest in a number of major Russian corruption scandals and has been portrayed by investigators as potentially one of the biggest money-laundering operations ever uncovered in the United States. U.S. and New York City authorities have seized about $20 million at the Bank of New York, along with transaction records, a U.S. law enforcement source said. The seizure, first reported in the New York Times, was made by the Russian Organized Crime Task Force, a joint operation of the FBI and New York police.

Money laundering and capital flight have been major problems for Russia's fledgling democratic government since its inception eight years ago, with tens of billions of dollars pouring out of the country. Many wealthy Russians, particularly those who made their fortunes illegally, have sought to hide their money overseas.

Last week, the Bank of New York suspended two Russian-born senior officers as news of the U.S. investigation became public. One of the executives, Natasha Gurfinkel Kagalovsky, is a senior vice president of the bank and supervised its East European division. Her husband is Konstantin Kagalovsky, who served as Russia's representative to the International Monetary Fund from 1992 to 1995; he has been in private business for the past several years, and is now vice president of Yukos, one of Russia's largest oil companies.

The Kagalovskys' attorney, Stanley Arkin, a prominent New York defense lawyer, said in a statement that his clients believe "it would be inappropriate to comment publicly while the investigations were in progress. Unfortunately, by not doing so, they have become the focus of highly unfair press coverage. . . . Konstantin and Natasha wish to state unequivocally that they have never been involved in money-laundering in any way, shape or form. Nor do they have any knowledge of such activity."

The other suspended banker was identified as Lucy Edwards, who worked in the bank's London office and is the wife of Russian businessman Peter Berlin.

Bank of New York officials said they are cooperating with U.S. authorities in the investigation, but they noted that the bank has not been accused of any wrongdoing.

The Wall Street Journal and USA Today have reported that some laundered money may have been IMF funds lent to Russia to help shore up its faltering economy.

The IMF has said it is taking the allegations seriously and is looking into the matter.

In Moscow, the probe has generated less attention than a separate set of accusations leveled at President Boris Yeltsin's government.

The Italian newspaper Corriere della Sera reported Wednesday that the Swiss construction firm Mabetex, which renovated the Kremlin, gave more than $1 million to Yeltsin and his family.

The newspaper alleged that Mabetex routed the money to a foreign bank account controlled by Kremlin manager Pavel Borodin, who in turn made it available to Yeltsin. The Kremlin denied the report.

Borodin, as well as his wife and other members of Yeltsin's administration, are targets of a Swiss money-laundering investigation.