WASHINGTON -- Chances are about two out of three that Russia could default on a foreign loan, the U.S. Congress was told as its new Republican majority prepares to review U.S. credit and aid policies with a skeptical eye.


The General Accounting Office responded to a request from Senator Jim Sasser, outgoing chairman of the Senate Budget Committee, by estimating "long-run probability of default" of 170 countries. It figured the chances for Russia at 67.6 percent -- 676 chances out of 1,000 -- whether the loan is for a year, five years, 10 or 30.


The report, dated Dec. 19, was made available this week.


When a country defaults on a loan the result is usually a negotiation that ends in an agreement to stretch the payments out over years.


Since the collapse of the Soviet Union, Russia has fallen behind on many of its payments. They include payments on loans -- guaranteed by the U.S. government -- to pay for grain and other food supplies.


In October, the United States agreed to delay payments on $900 million worth of Russian debt.


Senator Jesse Helms, who will chair the Senate Foreign Relations Committee beginining next month, has described some U.S. aid as money thrown down a "rat hole."


Russia owes about $110 billion to governments, banks and other creditors abroad. It is about $400 million in arrears on private debt interest for 1993 and 1994 alone, according to Mikhail Kasyanov, in charge of debt negotiations at the Russian Finance Ministry.


The GAO was even more pessimistic about chances of repayment from other former Soviet republics. Its estimate for Ukraine was 80.7 percent, or less than one chance in five.


For a limited number of countries such as Britain, France, Germany, Japan and Switzerland, the GAO rates the chance of default as zero. These are financially stable countries with a long record of prompt payment on their debts.


The GAO based its ratings on the prices at which government debt has been traded on open markets.