Tokyo stocks sank Tuesday morning, with the benchmark Nikkei sliding over 2 percent, as the yen strengthened against the U.S. dollar on expectations the Federal Reserve will decide on a large interest rate cut this week. Stocks were weak from the outset and extended losses, with insurance and bank shares dropping on falls in U.S. and Japanese long-term interest rates. Automakers and other exporters also slid on the strong yen.