Broad decline on Asian stock markets

The biggest loser in early trading was Japan's Nikkei 225, which had fallen 3.3 percent by lunchtime. The broader Topix index also fell 2.0 percent.

South Korea's Kospi fell 2.7 percent after chip giant Samsung Electronics, among others, lost about 7 percent.

In China, the movements were less dramatic. The Shanghai Composite Index was unchanged while Shenzhen fell 0.2 percent.

Hong Kong's Hang Seng fell 0.3 percent.