Analysts nervously watch Japan economy

Japanese stock markets fell more than 5 percent Monday as the country's manufacturers shuttered plants to assess damage and deal with power shortages, and the nation's economy wrestled with the impact of not only a natural disaster but lingering concerns about nuclear safety.

The Nikkei index of major Tokyo Stock Exchange companies fell sharply as trading opened for the first full day since the earthquake and tsunami struck Friday.

The world's third-largest economy was hobbled by a crisis that will challenge its financial system and energy infrastructure, as well as its capacity for dealing with a humanitarian disaster.

The first working day since the quake struck will dawn to rolling blackouts and hoarding, despite the Bank of Japan's vow to keep the economy on track. Central bank Governor Masaaki Shirakawa said over the weekend that the bank was prepared to inject "massive" amounts of money into the economy to keep the country's financial system stable and its trading system functioning.

Analysts warned that extended power disruptions or larger-than-expected damage to manufacturers could undercut a global economic recovery.

The insured property losses from the quake could amount to between $14 billion and $35 billion, according to Air Worldwide, a risk consulting company.

The weekend's events are likely to shape trading worldwide amid expectations that problems at the country's nuclear facilities may prompt countries to rethink the use of nuclear power and boost demand -- and prices -- for oil and other fuels.

But the global impact could be unpredictable in an era when markets, investors and policymakers have become increasingly concerned about the way shocks in one country can ripple through the world in unexpected ways.