NEW YORK - Financial markets tumbled through another difficult session Monday ahead of a planned early afternoon House vote on an unpopular $700 billion plan to rescue troubled financial companies and as investors examined a deal for Wachovia Corp. The Dow Jones industrial average fell more than 200 points, while demand for safe-haven buying in government debt remained high ahead of the vote.

Wall Street fears the government's plan to buy up toxic debt wouldn't be sufficient to resuscitate nearly frozen credit markets.

Investors also reviewed the buyout at Wachovia. The Federal Deposit Insurance Corp. said Monday Citigroup Inc. will acquire Wachovia's banking operations and that the deal protects Wachovia debtholders - a welcome prospect for investors given the strains in the credit markets. Investors had been worried about Wachovia's stability as it grappled with mounting losses over souring mortgage debt. Citi rose 69 cents, or 3.4 percent, to $20.84.

Investors appeared to find some reassurance in a move by the Federal Reserve and other countries' central banks to pump money into the world's credit markets.

The news comes as President Bush and congressional leaders looked to shore up support for the rescue measure, which they and many on Wall Street believe is a difficult but necessary step to revive moribund credit markets. Banks and other financial houses are hesitant to lend to one another because of fears about bad mortgage debt on companies' books.

Tight lending conditions make it hard and expensive for businesses and consumers to get loans, which can hurt the economy.

While congressional leaders said they had the headcount to pass the vote - a Senate vote could come as early as Wednesday - investors were likely to be unnerved until the votes are complete.

Credit markets remained strained Monday but improved after the Fed's injection. The yield on the 3-month Treasury bill, considered the safest short-term investment, fell to 0.75 percent from 0.87 percent late Friday. The yield was lower before the Fed's action. The yield on the T-bill falls as demand grows; investors are at times willing to take the slimmest returns to safeguard their principal. The yield on the benchmark 10-year Treasury note fell to 3.69 percent from 3.84 percent late Thursday.

Marc Pado, U.S. market strategist at Cantor Fitzgerald, said investors are nervous that lawmakers' response to credit troubles doesn't apply enough medicine to the financial system's wounds. He pointed to another round of troubles at banks in the U.S. and Europe.

"Things are dying and breaking apart while they sit there and vote on this thing," he said.