The Tokyo Stock Exchange's Nikkei 225 index is down 2.8 percent, and the broader Topix index has fallen 1.1 percent.
The South Korean stock market is hit even harder. The Kospi has plunged 6.6 percent, one of the biggest losses.
In Hong Kong, however, developments are going against the grain and the Hang Seng index is rising 1.7 percent.
Shanghai is down 0.6 percent and Shenzhen is down 0.3 percent.
