Japan's Nikkei 225 average plummeted 6.18% Monday over uncertainty about the economic impact of the powerful earthquake that slammed the nation on Friday.
The earthquake, the largest on record to ever hit Japan, and the ensuing tsunami, have killed thousands and caused widespread destruction throughout the country.
Chief among the concerns Monday morning in Tokyo was the state of numerous volatile nuclear reactors that were at risk of overheating, according to the Japanese government. When reactors overheat, there is the chance for radioactive gasses to be vented into the atmosphere, causing a major public health risk for populations near the reactors.
"The earthquake, tsunami and the nuclear incident have been the biggest crisis Japan has encountered in the 65 years since the end of World War Two," Japanese Prime Minister Naoto Kan said at a news conference Sunday.
Critical infrastructure and industrial centers were also affected, raising concerns over how quickly Japan's economy could recover after the natural disaster.
Indeed, as many as 2 million people were without power, and 1.4 million were without water on Monday, the Japanese government said.
The Bank of Japan injected a record $183 billion of cash into the financial system in a bid ensure stability in financial markets. The central bank also doubled its asset purchase program, an expansionary move, in hopes of easing the economic damage caused by the natural disaster.
European stocks opened lower, but then swung into positive territory as traders mulled the global consequences of Japan's economy, the third largest in the world, faltering.
American futures pointed to a modestly lower open on wall street. Dow Jones Industrial Average futures recently edged lower by 29 points to 11974.
Oil also slid more than 2% to $99.15 on concerns Japanese demand for oil would sink.
The vast majority of Nikkei 225 components, such as electronics-maker Sony and automaker Toyota, sustained steep losses. However, certain issues that specialize in construction and manufacturing bucked the trend and gained on expectations they would get a boost from the rebuilding effort.