TOKYO— World stock markets tumbled today as investors reacted coolly to Washington's $700 billion bank bailout deal, recognizing that cleaning up the bad debt mess will take a long time and likely drag on global economic growth for the foreseeable future.

Anxiety about spreading fallout from the U.S. financial meltdown grew on news that Belgium, the Netherlands and Luxembourg pledged more than 11 billion euros ($16 billion) to Dutch-Belgian bank and insurance giant Fortis NV to keep it from insolvency.

As trading opened in Europe, Britain's FTSE 100 sank 2.2 percent, France's CAC-40 and Germany's DAX both fell 2.6 percent.

"There's an increasing realization that the cleanup and the mending of all that's gone wrong is going to take an extended period to work through, and we're going to see an extended recovery period," said Jamie Spiteri, senior dealer at Shaw Stockbroking in Sydney.

Hong Kong's Hang Seng Index plunged 4.31 percent to 17,876.41, and Tokyo's benchmark Nikkei lost 1.3 percent to close at 11,743.61. Key indices in India, Thailand, South Korea and Australia also fell.

"They're worried that another fire is starting in Europe," said Castor Pang, an analyst at Sun Hung Kai Financial in Hong Kong, referring to the Fortis news.

After days of intense talks, the White House and Congressional leaders agreed Sunday to a $700 billion public bailout of the ailing financial industry after lawmakers insisted on sharing spending controls with the administration of President George W. Bush.

The biggest U.S. bailout in history, which goes to the House for a vote today and to the Senate later in the week, would give the administration broad power to use taxpayers' money to purchase billions of home mortgage-related assets held by cash-starved financial firms.

But even if the plan helps stabilize credit markets, the outlook for the U.S. economy remains grim, with unemployment at a five-year high of 6.1 percent and expected to climb higher. That's likely going to weaken demand for exports from Asia and Europe.

Furthermore, there are plenty of banks still in trouble, and it may take time before the bailout plan helps them.

Takahiko Murai, equities general manager at Nozomi Securities in Tokyo, said investors are questioning the effectiveness and details of the plan, including the government's ultimate purchasing price of the bad assets.

U.S. stock index futures fell, suggesting Wall Street would open lower today. Dow Jones industrial average futures were down 171 points to 10,976, while Standard & Poor's 500 index futures were down 20.8 points to 1,193.