TOKYO, Feb. 2 (Xinhua) -- Tokyo stocks opened lower Friday as U.S. Treasury yields rising again overnight underscored concerns about inflation with data showing a tight labor market and rising labor costs in the U.S. adding to investors' jitters.

As of 9:15 a.m. local time, the 225-issue Nikkei Stock Average lost 199.82 points, or 0.85 percent, from Thursday to 23,286.29.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, dropped 9.27 points, or 0.50 percent, to 1,861.17.

Securities, air transportation and machinery issues comprised those that retreated the most in the opening minutes after the morning bell.