TOKYO, March 28 (Xinhua) -- Tokyo stocks lost ground Wednesday morning as declines on Wall Street overnight soured the market mood, while ex-dividend selling also sent the index lower.

The 225-issue Nikkei Stock Average dropped 377.73 points, or 1.77 percent, from Tuesday to 20,939.59.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, lost 28.90 points, or 1.68 percent, at 1,688.23.

Mining, nonferrous metal and electric appliance-liked issues comprised those that declined the most by the morning break.