Asian stock markets tumbled Friday, with Hong Kong and South Korea down about 5 percent, as fears mounted over the fallout from Dubai's massive debt problems and the dollar continued its slide against the Japanese yen.

It was the region's second day of losses and followed a rout in European markets. Oil, meanwhile, dived to near $74 a barrel.

Investors cut back their riskier bets on equities and commodities after Dubai World, the emirate's main development engine, announced it was asking creditors to delay paying back its $60 billion debt.

The news triggered fears of a massive default and a wave of heavy losses at banks and companies exposed to its debt that could cause more financial pain just as the global economy is starting to recover.

Also dampening the mood was the slumping dollar, which weakened to a new 14-year low below 85 yen, dragging down shares of Japanese exporters like automaker Nissan and electronics maker Sharp.

"Investors were searching for shelter against the increased volatility and falls in risky assets," Dariusz Kowalczyk, chief investment strategist for SJS Markets in Hong Kong, said in a note. "Many chose to opt for the Japanese yen."

In Tokyo, the Nikkei 225 stock average fell 301.72 points, or 3.2 percent, to 9,081.52. Hong Kong's main index dived 1,111.28, or 5 percent, to 21,099.13.

Elsewhere, South Korea's Kospi benchmark plummeted 4.7 percent to 1,524.50 and Australia's index dropped 2.9 percent. China's main Shanghai stock measure was off 2.4 percent.

Certain banks got hit especially hard amid jitters about any losses they might suffer from their exposure to Dubai World. In Hong Kong trade, HSBC tanked 6.1 percent and Standard Chartered fell 5.8 percent; both British-based banks have substantial Middle East operations.

Uncertainty over the ripple effects from Dubai World's financial woes sent European markets plummeting Thursday, with benchmarks in Britain, Germany and France all losing more than 3 percent.

U.S. markets were closed Thursday for the Thanksgiving holiday. But Friday was likely to be a rough session on Wall Stree with futures pointing sharply lower. Dow futures were down 327, or 3.1 percent, to 10,115.

Oil prices retreated in Asian trade, with benchmark crude for January delivery falling $3.87 to $74.06 a barrel.

The dollar was lower at 86.05 yen from 86.54 yen after swooning as low as 84.81. The euro fell to $1.4850 from $1.5021.