Asian stock markets tumbled Tuesday, with Hong Kong and South Korea indexes down around three per cent, after relentless fears about the financial system and world economy drove Wall Street to its worst finish in nearly 12 years.

Every major market shuddered from losses across a range of sectors, from banks to technology firms, exporters and commodities, wiping out solid gains from the previous day.

Tokyo's benchmark languished near a 26-year low as news that Nomura Holdings, Japan's biggest broker, will raise billions more in capital by selling shares added to worries about the financial sector.

Most Asian exchanges advanced strongly Monday on reports the U.S. government may take a greater stake in tottering financial giant Citigroup.

But concerns that Citigroup and other banks will keep suffering severe losses flared overnight amid pessimism about a quick economic recovery and doubts the government can return the reeling financial system to working order.

As the administration of U.S. President Barack Obama tried to pacify fears, saying it would launch a revamped bank rescue program this week, U.S. investors hammered stocks. The Dow Jones and Standard & Poor's 500 indexes plummeted to their lowest closes since 1997.

"Investors are just selling out in disgust across the board — disgust with the market, disgust with the financial problems," said Lorraine Tan, director of equities research at Standard & Poor's in Singapore.

"The government seems to keep throwing in money, but there doesn't seem to be any end to the declines or solutions to the problems," she said.

In Japan, the Nikkei 225 stock average lost 107.60 points, or 1.5 per cent, to 7,268.56, though selling eased somewhat as the government signalled it may prop up stock prices, possibly by buying shares with public funds. Nomura dived 9.3 per cent.

China takes a hit

Hong Kong's Hang Seng sank 376.58, or 2.9 per cent, to 12,798.52, while South Korea's Kospi fell 3.2 per cent to 1,063.88.

Mainland Chinese shares, among the year's best performers, got slammed, and the Shanghai benchmark plunged 4.6 per cent.

Sentiment there also took a hit after China's central bank said the country's economic downturn could worsen and warned the risk of deflation is "quite big" amid collapsing consumer demand.

Elsewhere, Australia's stock measure was off 0.6 per cent, and Singapore's benchmark lost 1.4 per cent. Indexes in Taiwan and India shed about one per cent.

On Monday, U.S. investors seemed unconvinced after regulators promised to ensure the viability of banks by providing capital and said they would start conducting "stress tests" on Wednesday to gauge the health of financial firms.

Amid the assurances, however, came more reports of financial gloom.

Struggling insurer American International Group Inc. said it's evaluating "potential new alternatives" to tackle its financial problems amid reports it will soon announce a $60 billion loss and ask the government for more aid.

After the markets closed, JPMorgan Chase said it was slashing its quarterly dividend to preserve capital in case economic conditions drastically worsen.

The Dow plunged 250.89, or 3.4 per cent, to 7,114.78. It last closed this low on May 7, 1997 when it finished at 7,085.65. The Dow hasn't traded below the 7,000 mark since October 1997.

While S&P 500 managed to close above its Nov. 21 trading low, considered a key threshold among investors, it still took a beating.

The benchmark fell 26.72, or 3.5 per cent, to 743.33. It was the lowest close since April 11, 1997.

Stock futures suggested Wall Street would rise modestly Tuesday.

Dow futures were up 52, or 0.7 per cent, at 7,168 and S&P500 futures were up six, or 0.8 per cent, at 751.