Tokyo stocks plunged sharply in the morning session of Monday, with the Nikkei index briefly hitting a 2-week low tracking Wall Street losses. The 225-issue Nikkei Stock Average was down 166.55 points, or 1. 15 percent, at 14,262.71, after briefly falling as low as 14,224. 47, its lowest intraday level since April 16. The broader Topix index of all First Section issues on the Tokyo Stock Exchange shed 12.63 points, or 1.08 percent, at 1,157. 36. Decliners included paper and pulp, glass, shipping and automaker issues.