Tokyo stocks plunged Wednesday, with the key Nikkei index ending at a fresh three-month low below 9,700. The 225-issue Nikkei stock average slid 282.45 points, or 2.85 percent, to close at 9,614.60, its lowest finish since Aug. 12.

The broader Topix of all first section issues on the Tokyo Stock Exchange dropped 20.25 points, or 2.08 percent, to 953.19, its lowest close since Aug. 13.

Export-related technology issues, including Sony and TDK, came under selling pressure after U.S. shares fell for the fourth straight session. News that foreign investors sharply cut back on buying of U.S. Treasury securities in September, purchasing a net $5.6 billion, down from August's $25.2 billion, also fueled worries.

In addition, investor sentiment was dampened by concerns of possible terror attacks following news reports that shots were fired near the Japanese Embassy in Baghdad early Tuesday morning, brokers said.