BEIJING, April 27 (Xinhuanet) -- Goldman Sachs made 3.7 billion U.S. dollars three years ago by placing "bets" against mortgage-linked securities, U.S. senator Carl Levin said on Tuesday.

According to Bloomberg News, the Michigan Democrat released evidence which shows "Goldman repeateadly put its own interest and profit ahead of the interests of its clients."

The documents are shown before confrontation on Congress tomorrow between Levin's panel and seven Goldman Sachs employees.

Goldman's CEO Lloyd Blankfein is among those set to answer enquiries.

"Goldman made billions of dollars from betting against the housing market, and to sell to customers at the meanwhile you're betting against what you're selling - we think it uncommon and they have a lot to answer for," said Levin, Washington Post reported.

Internal e-mails, however, also suggest the Goldman's actions to bet against the housing market yielded it considerable profit.