NEW YORK (CNNMoney) -- Investors around the world were rattled Friday after a massive earthquake and tsunami struck Japan, adding another layer of uncertainty to already jittery markets.
Asian markets, which were falling before the tsunami hit, ended sharply lower. Japan's benchmark Nikkei index declined 1.7%, while the yen rose against the dollar.
Nikkei stock futures, which reflect trader's outlook for the index, were down 275 points on the Chicago Mercantile Exchange.
Stocks in the United States and Europe were lower but showed some resilience after a sharp sell off in the previous session.
The disaster adds another element of uncertainty to a market already nervous about geopolitical events in North Africa and the Middle East.
As a result, investors were shying away from more risky assets on Friday, including stocks and crude oil. The dollar, considered a safe haven by global investors, rose sharply against the euro and the U.K. pound.
But economists urged caution, saying it is too soon to speculate about the possible impact of the tsunami.
"There is no way to assess even the direct damage to Japan's economy, or to the global economy, that this will cause," said Carl Weinberg, chief economist at High Frequency Economics.
While it is impossible to estimate the toll of the disaster, "experience tells us that the economic shock can be, and likely will be, much bigger than anyone can imagine," said Weinberg.
Analysts at Japanese investment bank Nomura Securities said the direct human and economic costs could be significant, but it is too early to provide accurate estimates.
Japan was hit by a 7.3-magnitude earthquake in 1995, which hurt the nation's economy in the short run, but the long-term impact of that quake was limited, according to Nomura.
Stocks in the United States were lower in early trading Friday, one day after indexes fell sharply amid concerns about a planned "Day of Rage" protest in Saudi Arabia, one of the world's largest crude oil producers.
In Europe, Britain's FTSE 100 fell 0.3%, the DAX in Germany fell 0.9% and France's CAC 40 both lost 0.8%.
Commodities also took a hit, with oil and metals prices falling. Oil prices fell below $100 a barrel, while gold fell near $1,400 an ounce.