WASHINGTON (Reuters) - In the most damning official U.S. report yet produced on Wall Street's role in the financial crisis, a Senate panel accused powerhouse Goldman Sachs of misleading clients and manipulating markets, while also condemning greed, weak regulation and conflicts of interest throughout the financial system.

Carl Levin, chairman of the Senate Permanent Subcommittee on Investigations, one of Capitol Hill's most feared panels, has a history with Goldman Sachs.

He clashed publicly with its Chief Executive Lloyd Blankfein a year ago at a hearing on the crisis.

The Democratic lawmaker again tore into Goldman at a press briefing on his panel's 639-page report, which is based on a review of tens of millions of documents over two years.

Levin accused Goldman of profiting at clients' expense as the mortgage market crashed in 2007. "In my judgment, Goldman clearly misled their clients and they misled Congress," he said, reading glasses perched as ever on the tip of his nose.

A Goldman Sachs spokesman said, "While we disagree with many of the conclusions of the report, we take seriously the issues explored by the subcommittee."