NEW YORK (CNNMoney) -- Stocks in Japan opened higher Wednesday morning, one day after the island nation's main market index suffered one of its biggest drops on record.
The Nikkei 225 index, the most prominent measure of Tokyo market stocks, opened 6% higher but then began sliding. Two hours into trading, the index was up 380 points, or 4.42%.
The rebound comes after intense selling in the previous two sessions. On Tuesday, the index plunged 10.6%, marking the third worst one-day plunge in the Nikkei's history.
Investors in Japan have been stunned by the devastation caused by last week's earthquake and tsunami, including an increasingly dire situation at the Fukushima Daiichi nuclear power plant.
A second fire was discovered Wednesday at the stricken nuclear facility located about 138 miles north of Tokyo. A handful of workers have been struggling to contain a dangerous radiation threat there following three explosions and another fire on Tuesday.
The plant was crippled after a 9.0-earthquake, the fifth-largest worldwide since records began, struck off Japan's coast on March 11. Within an hour, a wall of water measuring up to 30 feet high swept across the Japanese coast, destroying entire towns and villages in its path.
The death toll has risen to 3,373, according to Japan's National Police Agency. At least 7,558 people were still missing as of Wednesday morning, and 1,990 were injured.
Economists say it is too soon to accurately estimate the financial toll of the disaster, but one expert said Tuesday that losses could exceed the record $125 billion that Hurricane Katrina caused in 2005.
In a statement, Atsushi Saito, the chief executive of the Tokyo Stock Exchange Group, attributed the selling to worries about "the degradation of social infrastructure" and the damaged nuclear power plant.
But he said Japan's experience recovering from past earthquakes "should not be underestimated" and that he believes "the stock market will calm down soon."
"I believe that the Tokyo Stock Exchange in its role as an important social infrastructure should continue to provide opportunities for stock trading," he added. "I would appreciate it if all investors and trading participants would respond in a calm and orderly manner."
Elsewhere in Asia, markets opened higher. Hong Kong's Hang Seng index gained 0.61% while China's Shanghai Composite advanced 0.28%.
Meanwhile, stocks in the United States recovered some ground late Tuesday but ended sharply lower as investors looked past a somewhat positive statement from the Federal Reserve to focus on events in Japan. 
