Dangerous levels of radiation began leaking from a crippled nuclear plant Tuesday, forcing Japan to order 140,000 people to stay indoors. Japan’s prime minister also warned that more leaks could occur.

In the U.S., the Dow Jones industrial average is down 281 points, or 2.2 percent, to 11,645 in early trading.

The Standard & Poor’s 500 index is down 35 points, or 2.7 percent, at 1,261. The Nasdaq composite index is down 77, or 2.8 percent, at 2,623.

Investors flocked to the relative safety of U.S. Treasurys, sending prices higher and yields lower. The yield on the 10-year Treasury note dropped to 3.23 percent from 3.36 percent late Monday.